diff --git a/.flake8 b/.flake8
index 5735456ae7d..4ff88403244 100644
--- a/.flake8
+++ b/.flake8
@@ -29,6 +29,8 @@ ignore =
     B950,
     W191,
     E124, # closing bracket, irritating while writing QB code
+    E131, # continuation line unaligned for hanging indent
+    E123, # closing bracket does not match indentation of opening bracket's line
 
 max-line-length = 200
 exclude=.github/helper/semgrep_rules
diff --git a/erpnext/accounts/doctype/pos_invoice/pos_invoice.json b/erpnext/accounts/doctype/pos_invoice/pos_invoice.json
index 0c6e7edeb02..b8500270d1a 100644
--- a/erpnext/accounts/doctype/pos_invoice/pos_invoice.json
+++ b/erpnext/accounts/doctype/pos_invoice/pos_invoice.json
@@ -264,7 +264,6 @@
    "print_hide": 1
   },
   {
-   "allow_on_submit": 1,
    "default": "0",
    "fieldname": "is_return",
    "fieldtype": "Check",
@@ -1573,7 +1572,7 @@
  "icon": "fa fa-file-text",
  "is_submittable": 1,
  "links": [],
- "modified": "2021-10-05 12:11:53.871828",
+ "modified": "2022-03-22 13:00:24.166684",
  "modified_by": "Administrator",
  "module": "Accounts",
  "name": "POS Invoice",
@@ -1623,6 +1622,7 @@
  "show_name_in_global_search": 1,
  "sort_field": "modified",
  "sort_order": "DESC",
+ "states": [],
  "timeline_field": "customer",
  "title_field": "title",
  "track_changes": 1,
diff --git a/erpnext/accounts/doctype/pos_invoice/pos_invoice.py b/erpnext/accounts/doctype/pos_invoice/pos_invoice.py
index 9115ee88541..96975e9d116 100644
--- a/erpnext/accounts/doctype/pos_invoice/pos_invoice.py
+++ b/erpnext/accounts/doctype/pos_invoice/pos_invoice.py
@@ -17,7 +17,11 @@ from erpnext.accounts.doctype.sales_invoice.sales_invoice import (
 )
 from erpnext.accounts.party import get_due_date, get_party_account
 from erpnext.stock.doctype.batch.batch import get_batch_qty, get_pos_reserved_batch_qty
-from erpnext.stock.doctype.serial_no.serial_no import get_pos_reserved_serial_nos, get_serial_nos
+from erpnext.stock.doctype.serial_no.serial_no import (
+	get_delivered_serial_nos,
+	get_pos_reserved_serial_nos,
+	get_serial_nos,
+)
 
 
 class POSInvoice(SalesInvoice):
@@ -179,12 +183,7 @@ class POSInvoice(SalesInvoice):
 			)
 
 	def validate_delivered_serial_nos(self, item):
-		serial_nos = get_serial_nos(item.serial_no)
-		delivered_serial_nos = frappe.db.get_list(
-			"Serial No",
-			{"item_code": item.item_code, "name": ["in", serial_nos], "sales_invoice": ["is", "set"]},
-			pluck="name",
-		)
+		delivered_serial_nos = get_delivered_serial_nos(item.serial_no)
 
 		if delivered_serial_nos:
 			bold_delivered_serial_nos = frappe.bold(", ".join(delivered_serial_nos))
@@ -212,9 +211,16 @@ class POSInvoice(SalesInvoice):
 			frappe.throw(error_msg, title=_("Invalid Item"), as_list=True)
 
 	def validate_stock_availablility(self):
-		if self.is_return or self.docstatus != 1:
+		if self.is_return:
 			return
+
+		if self.docstatus == 0 and not frappe.db.get_value(
+			"POS Profile", self.pos_profile, "validate_stock_on_save"
+		):
+			return
+
 		allow_negative_stock = frappe.db.get_single_value("Stock Settings", "allow_negative_stock")
+
 		for d in self.get("items"):
 			is_service_item = not (frappe.db.get_value("Item", d.get("item_code"), "is_stock_item"))
 			if is_service_item:
diff --git a/erpnext/accounts/doctype/pos_invoice/test_pos_invoice.py b/erpnext/accounts/doctype/pos_invoice/test_pos_invoice.py
index ee35614cdce..70f128e0e39 100644
--- a/erpnext/accounts/doctype/pos_invoice/test_pos_invoice.py
+++ b/erpnext/accounts/doctype/pos_invoice/test_pos_invoice.py
@@ -439,6 +439,7 @@ class TestPOSInvoice(unittest.TestCase):
 		)
 
 		si.get("items")[0].serial_no = serial_nos[0]
+		si.update_stock = 1
 		si.insert()
 		si.submit()
 
@@ -765,6 +766,76 @@ class TestPOSInvoice(unittest.TestCase):
 			pos_inv.delete()
 			pr.delete()
 
+	def test_delivered_serial_no_case(self):
+		from erpnext.accounts.doctype.pos_invoice_merge_log.test_pos_invoice_merge_log import (
+			init_user_and_profile,
+		)
+		from erpnext.stock.doctype.delivery_note.test_delivery_note import create_delivery_note
+		from erpnext.stock.doctype.serial_no.test_serial_no import get_serial_nos
+		from erpnext.stock.doctype.stock_entry.test_stock_entry import make_serialized_item
+
+		frappe.db.savepoint("before_test_delivered_serial_no_case")
+		try:
+			se = make_serialized_item()
+			serial_no = get_serial_nos(se.get("items")[0].serial_no)[0]
+
+			dn = create_delivery_note(item_code="_Test Serialized Item With Series", serial_no=serial_no)
+
+			delivery_document_no = frappe.db.get_value("Serial No", serial_no, "delivery_document_no")
+			self.assertEquals(delivery_document_no, dn.name)
+
+			init_user_and_profile()
+
+			pos_inv = create_pos_invoice(
+				item_code="_Test Serialized Item With Series",
+				serial_no=serial_no,
+				qty=1,
+				rate=100,
+				do_not_submit=True,
+			)
+
+			self.assertRaises(frappe.ValidationError, pos_inv.submit)
+
+		finally:
+			frappe.db.rollback(save_point="before_test_delivered_serial_no_case")
+			frappe.set_user("Administrator")
+
+	def test_returned_serial_no_case(self):
+		from erpnext.accounts.doctype.pos_invoice_merge_log.test_pos_invoice_merge_log import (
+			init_user_and_profile,
+		)
+		from erpnext.stock.doctype.serial_no.serial_no import get_pos_reserved_serial_nos
+		from erpnext.stock.doctype.serial_no.test_serial_no import get_serial_nos
+		from erpnext.stock.doctype.stock_entry.test_stock_entry import make_serialized_item
+
+		frappe.db.savepoint("before_test_returned_serial_no_case")
+		try:
+			se = make_serialized_item()
+			serial_no = get_serial_nos(se.get("items")[0].serial_no)[0]
+
+			init_user_and_profile()
+
+			pos_inv = create_pos_invoice(
+				item_code="_Test Serialized Item With Series",
+				serial_no=serial_no,
+				qty=1,
+				rate=100,
+			)
+
+			pos_return = make_sales_return(pos_inv.name)
+			pos_return.flags.ignore_validate = True
+			pos_return.insert()
+			pos_return.submit()
+
+			pos_reserved_serial_nos = get_pos_reserved_serial_nos(
+				{"item_code": "_Test Serialized Item With Series", "warehouse": "_Test Warehouse - _TC"}
+			)
+			self.assertTrue(serial_no not in pos_reserved_serial_nos)
+
+		finally:
+			frappe.db.rollback(save_point="before_test_returned_serial_no_case")
+			frappe.set_user("Administrator")
+
 
 def create_pos_invoice(**args):
 	args = frappe._dict(args)
diff --git a/erpnext/accounts/doctype/pos_invoice_merge_log/pos_invoice_merge_log.py b/erpnext/accounts/doctype/pos_invoice_merge_log/pos_invoice_merge_log.py
index 89af6ad4e57..d3a81fe61dc 100644
--- a/erpnext/accounts/doctype/pos_invoice_merge_log/pos_invoice_merge_log.py
+++ b/erpnext/accounts/doctype/pos_invoice_merge_log/pos_invoice_merge_log.py
@@ -5,7 +5,6 @@
 import json
 
 import frappe
-import six
 from frappe import _
 from frappe.core.page.background_jobs.background_jobs import get_info
 from frappe.model.document import Document
@@ -66,7 +65,9 @@ class POSInvoiceMergeLog(Document):
 					frappe.throw(msg)
 
 	def on_submit(self):
-		pos_invoice_docs = [frappe.get_doc("POS Invoice", d.pos_invoice) for d in self.pos_invoices]
+		pos_invoice_docs = [
+			frappe.get_cached_doc("POS Invoice", d.pos_invoice) for d in self.pos_invoices
+		]
 
 		returns = [d for d in pos_invoice_docs if d.get("is_return") == 1]
 		sales = [d for d in pos_invoice_docs if d.get("is_return") == 0]
@@ -83,7 +84,9 @@ class POSInvoiceMergeLog(Document):
 		self.update_pos_invoices(pos_invoice_docs, sales_invoice, credit_note)
 
 	def on_cancel(self):
-		pos_invoice_docs = [frappe.get_doc("POS Invoice", d.pos_invoice) for d in self.pos_invoices]
+		pos_invoice_docs = [
+			frappe.get_cached_doc("POS Invoice", d.pos_invoice) for d in self.pos_invoices
+		]
 
 		self.update_pos_invoices(pos_invoice_docs)
 		self.cancel_linked_invoices()
@@ -282,7 +285,14 @@ def get_all_unconsolidated_invoices():
 	pos_invoices = frappe.db.get_all(
 		"POS Invoice",
 		filters=filters,
-		fields=["name as pos_invoice", "posting_date", "grand_total", "customer"],
+		fields=[
+			"name as pos_invoice",
+			"posting_date",
+			"grand_total",
+			"customer",
+			"is_return",
+			"return_against",
+		],
 	)
 
 	return pos_invoices
@@ -327,19 +337,74 @@ def unconsolidate_pos_invoices(closing_entry):
 		cancel_merge_logs(merge_logs, closing_entry)
 
 
+def split_invoices(invoices):
+	"""
+	Splits invoices into multiple groups
+	Use-case:
+	If a serial no is sold and later it is returned
+	then split the invoices such that the selling entry is merged first and then the return entry
+	"""
+	# Input
+	# invoices = [
+	# 	{'pos_invoice': 'Invoice with SR#1 & SR#2', 'is_return': 0},
+	# 	{'pos_invoice': 'Invoice with SR#1', 'is_return': 1},
+	# 	{'pos_invoice': 'Invoice with SR#2', 'is_return': 0}
+	# ]
+	# Output
+	# _invoices = [
+	# 	[{'pos_invoice': 'Invoice with SR#1 & SR#2', 'is_return': 0}],
+	# 	[{'pos_invoice': 'Invoice with SR#1', 'is_return': 1}, {'pos_invoice': 'Invoice with SR#2', 'is_return': 0}],
+	# ]
+
+	_invoices = []
+	special_invoices = []
+	pos_return_docs = [
+		frappe.get_cached_doc("POS Invoice", d.pos_invoice)
+		for d in invoices
+		if d.is_return and d.return_against
+	]
+	for pos_invoice in pos_return_docs:
+		for item in pos_invoice.items:
+			if not item.serial_no:
+				continue
+
+			return_against_is_added = any(
+				d for d in _invoices if d.pos_invoice == pos_invoice.return_against
+			)
+			if return_against_is_added:
+				break
+
+			return_against_is_consolidated = (
+				frappe.db.get_value("POS Invoice", pos_invoice.return_against, "status", cache=True)
+				== "Consolidated"
+			)
+			if return_against_is_consolidated:
+				break
+
+			pos_invoice_row = [d for d in invoices if d.pos_invoice == pos_invoice.return_against]
+			_invoices.append(pos_invoice_row)
+			special_invoices.append(pos_invoice.return_against)
+			break
+
+	_invoices.append([d for d in invoices if d.pos_invoice not in special_invoices])
+
+	return _invoices
+
+
 def create_merge_logs(invoice_by_customer, closing_entry=None):
 	try:
-		for customer, invoices in six.iteritems(invoice_by_customer):
-			merge_log = frappe.new_doc("POS Invoice Merge Log")
-			merge_log.posting_date = (
-				getdate(closing_entry.get("posting_date")) if closing_entry else nowdate()
-			)
-			merge_log.customer = customer
-			merge_log.pos_closing_entry = closing_entry.get("name") if closing_entry else None
+		for customer, invoices in invoice_by_customer.items():
+			for _invoices in split_invoices(invoices):
+				merge_log = frappe.new_doc("POS Invoice Merge Log")
+				merge_log.posting_date = (
+					getdate(closing_entry.get("posting_date")) if closing_entry else nowdate()
+				)
+				merge_log.customer = customer
+				merge_log.pos_closing_entry = closing_entry.get("name") if closing_entry else None
 
-			merge_log.set("pos_invoices", invoices)
-			merge_log.save(ignore_permissions=True)
-			merge_log.submit()
+				merge_log.set("pos_invoices", _invoices)
+				merge_log.save(ignore_permissions=True)
+				merge_log.submit()
 
 		if closing_entry:
 			closing_entry.set_status(update=True, status="Submitted")
diff --git a/erpnext/accounts/doctype/pos_invoice_merge_log/test_pos_invoice_merge_log.py b/erpnext/accounts/doctype/pos_invoice_merge_log/test_pos_invoice_merge_log.py
index c6d8179c40c..9e696f18b6a 100644
--- a/erpnext/accounts/doctype/pos_invoice_merge_log/test_pos_invoice_merge_log.py
+++ b/erpnext/accounts/doctype/pos_invoice_merge_log/test_pos_invoice_merge_log.py
@@ -391,3 +391,61 @@ class TestPOSInvoiceMergeLog(unittest.TestCase):
 			frappe.set_user("Administrator")
 			frappe.db.sql("delete from `tabPOS Profile`")
 			frappe.db.sql("delete from `tabPOS Invoice`")
+
+	def test_serial_no_case_1(self):
+		"""
+		Create a POS Invoice with serial no
+		Create a Return Invoice with serial no
+		Create a POS Invoice with serial no again
+		Consolidate the invoices
+
+		The first POS Invoice should be consolidated with a separate single Merge Log
+		The second and third POS Invoice should be consolidated with a single Merge Log
+		"""
+
+		from erpnext.stock.doctype.serial_no.test_serial_no import get_serial_nos
+		from erpnext.stock.doctype.stock_entry.test_stock_entry import make_serialized_item
+
+		frappe.db.sql("delete from `tabPOS Invoice`")
+
+		try:
+			se = make_serialized_item()
+			serial_no = get_serial_nos(se.get("items")[0].serial_no)[0]
+
+			init_user_and_profile()
+
+			pos_inv = create_pos_invoice(
+				item_code="_Test Serialized Item With Series",
+				serial_no=serial_no,
+				qty=1,
+				rate=100,
+				do_not_submit=1,
+			)
+			pos_inv.append("payments", {"mode_of_payment": "Cash", "account": "Cash - _TC", "amount": 100})
+			pos_inv.submit()
+
+			pos_inv_cn = make_sales_return(pos_inv.name)
+			pos_inv_cn.paid_amount = -100
+			pos_inv_cn.submit()
+
+			pos_inv2 = create_pos_invoice(
+				item_code="_Test Serialized Item With Series",
+				serial_no=serial_no,
+				qty=1,
+				rate=100,
+				do_not_submit=1,
+			)
+			pos_inv2.append("payments", {"mode_of_payment": "Cash", "account": "Cash - _TC", "amount": 100})
+			pos_inv2.submit()
+
+			consolidate_pos_invoices()
+
+			pos_inv.load_from_db()
+			pos_inv2.load_from_db()
+
+			self.assertNotEqual(pos_inv.consolidated_invoice, pos_inv2.consolidated_invoice)
+
+		finally:
+			frappe.set_user("Administrator")
+			frappe.db.sql("delete from `tabPOS Profile`")
+			frappe.db.sql("delete from `tabPOS Invoice`")
diff --git a/erpnext/accounts/doctype/pos_invoice_reference/pos_invoice_reference.json b/erpnext/accounts/doctype/pos_invoice_reference/pos_invoice_reference.json
index 205c4ede901..387c4b0f360 100644
--- a/erpnext/accounts/doctype/pos_invoice_reference/pos_invoice_reference.json
+++ b/erpnext/accounts/doctype/pos_invoice_reference/pos_invoice_reference.json
@@ -9,7 +9,9 @@
   "posting_date",
   "column_break_3",
   "customer",
-  "grand_total"
+  "grand_total",
+  "is_return",
+  "return_against"
  ],
  "fields": [
   {
@@ -48,11 +50,27 @@
    "in_list_view": 1,
    "label": "Amount",
    "reqd": 1
+  },
+  {
+   "default": "0",
+   "fetch_from": "pos_invoice.is_return",
+   "fieldname": "is_return",
+   "fieldtype": "Check",
+   "label": "Is Return",
+   "read_only": 1
+  },
+  {
+   "fetch_from": "pos_invoice.return_against",
+   "fieldname": "return_against",
+   "fieldtype": "Link",
+   "label": "Return Against",
+   "options": "POS Invoice",
+   "read_only": 1
   }
  ],
  "istable": 1,
  "links": [],
- "modified": "2020-05-29 15:08:42.194979",
+ "modified": "2022-03-24 13:32:02.366257",
  "modified_by": "Administrator",
  "module": "Accounts",
  "name": "POS Invoice Reference",
@@ -61,5 +79,6 @@
  "quick_entry": 1,
  "sort_field": "modified",
  "sort_order": "DESC",
+ "states": [],
  "track_changes": 1
 }
\ No newline at end of file
diff --git a/erpnext/accounts/doctype/pos_profile/pos_profile.json b/erpnext/accounts/doctype/pos_profile/pos_profile.json
index 9c9f37bba27..11646a6517d 100644
--- a/erpnext/accounts/doctype/pos_profile/pos_profile.json
+++ b/erpnext/accounts/doctype/pos_profile/pos_profile.json
@@ -22,6 +22,7 @@
   "hide_images",
   "hide_unavailable_items",
   "auto_add_item_to_cart",
+  "validate_stock_on_save",
   "column_break_16",
   "update_stock",
   "ignore_pricing_rule",
@@ -351,6 +352,12 @@
   {
    "fieldname": "column_break_25",
    "fieldtype": "Column Break"
+  },
+  {
+   "default": "0",
+   "fieldname": "validate_stock_on_save",
+   "fieldtype": "Check",
+   "label": "Validate Stock on Save"
   }
  ],
  "icon": "icon-cog",
@@ -378,10 +385,11 @@
    "link_fieldname": "pos_profile"
   }
  ],
- "modified": "2021-10-14 14:17:00.469298",
+ "modified": "2022-03-21 13:29:28.480533",
  "modified_by": "Administrator",
  "module": "Accounts",
  "name": "POS Profile",
+ "naming_rule": "Set by user",
  "owner": "Administrator",
  "permissions": [
   {
@@ -404,5 +412,6 @@
   }
  ],
  "sort_field": "modified",
- "sort_order": "DESC"
+ "sort_order": "DESC",
+ "states": []
 }
\ No newline at end of file
diff --git a/erpnext/patches.txt b/erpnext/patches.txt
index 50050afd316..98e07783c11 100644
--- a/erpnext/patches.txt
+++ b/erpnext/patches.txt
@@ -357,3 +357,4 @@ erpnext.patches.v13_0.rename_non_profit_fields
 erpnext.patches.v13_0.enable_ksa_vat_docs #1
 erpnext.patches.v13_0.create_gst_custom_fields_in_quotation
 erpnext.patches.v13_0.update_expense_claim_status_for_paid_advances
+erpnext.patches.v13_0.set_return_against_in_pos_invoice_references
diff --git a/erpnext/patches/v13_0/set_return_against_in_pos_invoice_references.py b/erpnext/patches/v13_0/set_return_against_in_pos_invoice_references.py
new file mode 100644
index 00000000000..6af9617bcee
--- /dev/null
+++ b/erpnext/patches/v13_0/set_return_against_in_pos_invoice_references.py
@@ -0,0 +1,38 @@
+import frappe
+
+
+def execute():
+	"""
+	Fetch and Set is_return & return_against from POS Invoice in POS Invoice References table.
+	"""
+
+	POSClosingEntry = frappe.qb.DocType("POS Closing Entry")
+	open_pos_closing_entries = (
+		frappe.qb.from_(POSClosingEntry)
+		.select(POSClosingEntry.name)
+		.where(POSClosingEntry.docstatus == 0)
+		.run()
+	)
+	if open_pos_closing_entries:
+		open_pos_closing_entries = [d[0] for d in open_pos_closing_entries]
+
+	if not open_pos_closing_entries:
+		return
+
+	POSInvoiceReference = frappe.qb.DocType("POS Invoice Reference")
+	POSInvoice = frappe.qb.DocType("POS Invoice")
+	pos_invoice_references = (
+		frappe.qb.from_(POSInvoiceReference)
+		.join(POSInvoice)
+		.on(POSInvoiceReference.pos_invoice == POSInvoice.name)
+		.select(POSInvoiceReference.name, POSInvoice.is_return, POSInvoice.return_against)
+		.where(POSInvoiceReference.parent.isin(open_pos_closing_entries))
+		.run(as_dict=True)
+	)
+
+	for row in pos_invoice_references:
+		frappe.db.set_value("POS Invoice Reference", row.name, "is_return", row.is_return)
+		if row.is_return:
+			frappe.db.set_value("POS Invoice Reference", row.name, "return_against", row.return_against)
+		else:
+			frappe.db.set_value("POS Invoice Reference", row.name, "return_against", None)
diff --git a/erpnext/selling/page/point_of_sale/point_of_sale.py b/erpnext/selling/page/point_of_sale/point_of_sale.py
index 4efb1a03f7e..bf629824ad9 100644
--- a/erpnext/selling/page/point_of_sale/point_of_sale.py
+++ b/erpnext/selling/page/point_of_sale/point_of_sale.py
@@ -8,7 +8,7 @@ import frappe
 from frappe.utils.nestedset import get_root_of
 
 from erpnext.accounts.doctype.pos_invoice.pos_invoice import get_stock_availability
-from erpnext.accounts.doctype.pos_profile.pos_profile import get_item_groups
+from erpnext.accounts.doctype.pos_profile.pos_profile import get_child_nodes, get_item_groups
 
 
 def search_by_term(search_term, warehouse, price_list):
@@ -324,3 +324,17 @@ def set_customer_info(fieldname, customer, value=""):
 		contact_doc.set("phone_nos", [{"phone": value, "is_primary_mobile_no": 1}])
 		frappe.db.set_value("Customer", customer, "mobile_no", value)
 	contact_doc.save()
+
+
+@frappe.whitelist()
+def get_pos_profile_data(pos_profile):
+	pos_profile = frappe.get_doc("POS Profile", pos_profile)
+	pos_profile = pos_profile.as_dict()
+
+	_customer_groups_with_children = []
+	for row in pos_profile.customer_groups:
+		children = get_child_nodes("Customer Group", row.customer_group)
+		_customer_groups_with_children.extend(children)
+
+	pos_profile.customer_groups = _customer_groups_with_children
+	return pos_profile
diff --git a/erpnext/selling/page/point_of_sale/pos_controller.js b/erpnext/selling/page/point_of_sale/pos_controller.js
index ea8459f970b..6974bed4f1f 100644
--- a/erpnext/selling/page/point_of_sale/pos_controller.js
+++ b/erpnext/selling/page/point_of_sale/pos_controller.js
@@ -119,10 +119,15 @@ erpnext.PointOfSale.Controller = class {
 			this.allow_negative_stock = flt(message.allow_negative_stock) || false;
 		});
 
-		frappe.db.get_doc("POS Profile", this.pos_profile).then((profile) => {
-			Object.assign(this.settings, profile);
-			this.settings.customer_groups = profile.customer_groups.map(group => group.customer_group);
-			this.make_app();
+		frappe.call({
+			method: "erpnext.selling.page.point_of_sale.point_of_sale.get_pos_profile_data",
+			args: { "pos_profile": this.pos_profile },
+			callback: (res) => {
+				const profile = res.message;
+				Object.assign(this.settings, profile);
+				this.settings.customer_groups = profile.customer_groups.map(group => group.name);
+				this.make_app();
+			}
 		});
 	}
 
@@ -555,7 +560,7 @@ erpnext.PointOfSale.Controller = class {
 				if (this.item_details.$component.is(':visible'))
 					this.edit_item_details_of(item_row);
 
-				if (this.check_serial_batch_selection_needed(item_row))
+				if (this.check_serial_batch_selection_needed(item_row) && !this.item_details.$component.is(':visible'))
 					this.edit_item_details_of(item_row);
 			}
 
@@ -704,7 +709,7 @@ erpnext.PointOfSale.Controller = class {
 		frappe.dom.freeze();
 		const { doctype, name, current_item } = this.item_details;
 
-		frappe.model.set_value(doctype, name, 'qty', 0)
+		return frappe.model.set_value(doctype, name, 'qty', 0)
 			.then(() => {
 				frappe.model.clear_doc(doctype, name);
 				this.update_cart_html(current_item, true);
@@ -715,7 +720,14 @@ erpnext.PointOfSale.Controller = class {
 	}
 
 	async save_and_checkout() {
-		this.frm.is_dirty() && await this.frm.save();
-		this.payment.checkout();
+		if (this.frm.is_dirty()) {
+			// only move to payment section if save is successful
+			frappe.route_hooks.after_save = () => this.payment.checkout();
+			return this.frm.save(
+				null, null, null, () => this.cart.toggle_checkout_btn(true) // show checkout button on error
+			);
+		} else {
+			this.payment.checkout();
+		}
 	}
 };
diff --git a/erpnext/selling/page/point_of_sale/pos_item_details.js b/erpnext/selling/page/point_of_sale/pos_item_details.js
index a3ad0025943..1d720f7291a 100644
--- a/erpnext/selling/page/point_of_sale/pos_item_details.js
+++ b/erpnext/selling/page/point_of_sale/pos_item_details.js
@@ -60,12 +60,18 @@ erpnext.PointOfSale.ItemDetails = class {
 		return item && item.name == this.current_item.name;
 	}
 
-	toggle_item_details_section(item) {
+	async toggle_item_details_section(item) {
 		const current_item_changed = !this.compare_with_current_item(item);
 
 		// if item is null or highlighted cart item is clicked twice
 		const hide_item_details = !Boolean(item) || !current_item_changed;
 
+		if ((!hide_item_details && current_item_changed) || hide_item_details) {
+			// if item details is being closed OR if item details is opened but item is changed
+			// in both cases, if the current item is a serialized item, then validate and remove the item
+			await this.validate_serial_batch_item();
+		}
+
 		this.events.toggle_item_selector(!hide_item_details);
 		this.toggle_component(!hide_item_details);
 
@@ -83,7 +89,6 @@ erpnext.PointOfSale.ItemDetails = class {
 			this.render_form(item);
 			this.events.highlight_cart_item(item);
 		} else {
-			this.validate_serial_batch_item();
 			this.current_item = {};
 		}
 	}
@@ -103,11 +108,11 @@ erpnext.PointOfSale.ItemDetails = class {
 			(serialized && batched && (no_batch_selected || no_serial_selected))) {
 
 			frappe.show_alert({
-				message: __("Item will be removed since no serial / batch no selected."),
+				message: __("Item is removed since no serial / batch no selected."),
 				indicator: 'orange'
 			});
 			frappe.utils.play_sound("cancel");
-			this.events.remove_item_from_cart();
+			return this.events.remove_item_from_cart();
 		}
 	}
 
diff --git a/erpnext/selling/page/point_of_sale/pos_payment.js b/erpnext/selling/page/point_of_sale/pos_payment.js
index 1e9f6d7d920..b4ece46e6e1 100644
--- a/erpnext/selling/page/point_of_sale/pos_payment.js
+++ b/erpnext/selling/page/point_of_sale/pos_payment.js
@@ -170,20 +170,24 @@ erpnext.PointOfSale.Payment = class {
     });
 
 		frappe.ui.form.on('POS Invoice', 'coupon_code', (frm) => {
-			if (!frm.doc.ignore_pricing_rule && frm.doc.coupon_code) {
-				frappe.run_serially([
-					() => frm.doc.ignore_pricing_rule=1,
-					() => frm.trigger('ignore_pricing_rule'),
-					() => frm.doc.ignore_pricing_rule=0,
-					() => frm.trigger('apply_pricing_rule'),
-					() => frm.save(),
-					() => this.update_totals_section(frm.doc)
-				]);
-			} else if (frm.doc.ignore_pricing_rule && frm.doc.coupon_code) {
-				frappe.show_alert({
-					message: __("Ignore Pricing Rule is enabled. Cannot apply coupon code."),
-					indicator: "orange"
-				});
+			if (frm.doc.coupon_code && !frm.applying_pos_coupon_code) {
+				if (!frm.doc.ignore_pricing_rule) {
+					frm.applying_pos_coupon_code = true;
+					frappe.run_serially([
+						() => frm.doc.ignore_pricing_rule=1,
+						() => frm.trigger('ignore_pricing_rule'),
+						() => frm.doc.ignore_pricing_rule=0,
+						() => frm.trigger('apply_pricing_rule'),
+						() => frm.save(),
+						() => this.update_totals_section(frm.doc),
+						() => (frm.applying_pos_coupon_code = false)
+					]);
+				} else if (frm.doc.ignore_pricing_rule) {
+					frappe.show_alert({
+						message: __("Ignore Pricing Rule is enabled. Cannot apply coupon code."),
+						indicator: "orange"
+					});
+				}
 			}
 		});
 
diff --git a/erpnext/stock/doctype/serial_no/serial_no.py b/erpnext/stock/doctype/serial_no/serial_no.py
index bc30878789f..6d3969892f2 100644
--- a/erpnext/stock/doctype/serial_no/serial_no.py
+++ b/erpnext/stock/doctype/serial_no/serial_no.py
@@ -820,29 +820,60 @@ def auto_fetch_serial_number(
 	return sorted([d.get("name") for d in serial_numbers])
 
 
+def get_delivered_serial_nos(serial_nos):
+	"""
+	Returns serial numbers that delivered from the list of serial numbers
+	"""
+	from frappe.query_builder.functions import Coalesce
+
+	SerialNo = frappe.qb.DocType("Serial No")
+	serial_nos = get_serial_nos(serial_nos)
+	query = (
+		frappe.qb.select(SerialNo.name)
+		.from_(SerialNo)
+		.where((SerialNo.name.isin(serial_nos)) & (Coalesce(SerialNo.delivery_document_type, "") != ""))
+	)
+
+	result = query.run()
+	if result and len(result) > 0:
+		delivered_serial_nos = [row[0] for row in result]
+		return delivered_serial_nos
+
+
 @frappe.whitelist()
 def get_pos_reserved_serial_nos(filters):
 	if isinstance(filters, str):
 		filters = json.loads(filters)
 
-	pos_transacted_sr_nos = frappe.db.sql(
-		"""select item.serial_no as serial_no
-		from `tabPOS Invoice` p, `tabPOS Invoice Item` item
-		where p.name = item.parent
-		and p.consolidated_invoice is NULL
-		and p.docstatus = 1
-		and item.docstatus = 1
-		and item.item_code = %(item_code)s
-		and item.warehouse = %(warehouse)s
-		and item.serial_no is NOT NULL and item.serial_no != ''
-		""",
-		filters,
-		as_dict=1,
+	POSInvoice = frappe.qb.DocType("POS Invoice")
+	POSInvoiceItem = frappe.qb.DocType("POS Invoice Item")
+	query = (
+		frappe.qb.from_(POSInvoice)
+		.from_(POSInvoiceItem)
+		.select(POSInvoice.is_return, POSInvoiceItem.serial_no)
+		.where(
+			(POSInvoice.name == POSInvoiceItem.parent)
+			& (POSInvoice.docstatus == 1)
+			& (POSInvoiceItem.docstatus == 1)
+			& (POSInvoiceItem.item_code == filters.get("item_code"))
+			& (POSInvoiceItem.warehouse == filters.get("warehouse"))
+			& (POSInvoiceItem.serial_no.isnotnull())
+			& (POSInvoiceItem.serial_no != "")
+		)
 	)
 
+	pos_transacted_sr_nos = query.run(as_dict=True)
+
 	reserved_sr_nos = []
+	returned_sr_nos = []
 	for d in pos_transacted_sr_nos:
-		reserved_sr_nos += get_serial_nos(d.serial_no)
+		if d.is_return == 0:
+			reserved_sr_nos += get_serial_nos(d.serial_no)
+		elif d.is_return == 1:
+			returned_sr_nos += get_serial_nos(d.serial_no)
+
+	for sr_no in returned_sr_nos:
+		reserved_sr_nos.remove(sr_no)
 
 	return reserved_sr_nos