diff --git a/erpnext/accounts/doctype/payment_entry/payment_entry.py b/erpnext/accounts/doctype/payment_entry/payment_entry.py
index b4005436ec0..706644c9819 100644
--- a/erpnext/accounts/doctype/payment_entry/payment_entry.py
+++ b/erpnext/accounts/doctype/payment_entry/payment_entry.py
@@ -2795,6 +2795,9 @@ def get_open_payment_requests_for_references(references=None):
 		.where(PR.docstatus == 1)
 		.where(PR.outstanding_amount > 0)  # to avoid old PRs with 0 outstanding amount
 		.orderby(Coalesce(PR.transaction_date, PR.creation), order=frappe.qb.asc)
+		# unique tiebreaker so PRs sharing a transaction_date allocate in the same order on both engines
+		.orderby(PR.creation, order=frappe.qb.asc)
+		.orderby(PR.name, order=frappe.qb.asc)
 	).run(as_dict=True)
 
 	if not response:
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 8f0bc136458..bd96ae38cc9 100644
--- a/erpnext/selling/page/point_of_sale/point_of_sale.py
+++ b/erpnext/selling/page/point_of_sale/point_of_sale.py
@@ -464,6 +464,9 @@ def set_customer_info(fieldname: str, customer: str, value: str = ""):
 					& (DynamicLink.link_doctype == "Customer")
 				)
 				.orderby(Contact.is_primary_contact, order=Order.desc)
+				# tiebreaker: contacts tie on is_primary_contact (the common no-primary case) ->
+				# pick the same one on MariaDB and Postgres
+				.orderby(DynamicLink.parent, order=Order.asc)
 			)
 
 			contacts = query.run(pluck=DynamicLink.parent)
diff --git a/erpnext/stock/doctype/packed_item/packed_item.py b/erpnext/stock/doctype/packed_item/packed_item.py
index 5aff12994c9..9ec908c6b62 100644
--- a/erpnext/stock/doctype/packed_item/packed_item.py
+++ b/erpnext/stock/doctype/packed_item/packed_item.py
@@ -326,7 +326,8 @@ def update_packed_item_with_pick_list_info(main_item_row, pi_row):
 		},
 		["warehouse", "batch_no", "serial_no"],
 		as_dict=True,
-		order_by="qty desc",
+		# name tiebreaker: split pick-list rows can tie on qty -> pick the same warehouse/batch/serial on both engines
+		order_by="qty desc, name asc",
 	)
 
 	if not pl_row:
diff --git a/erpnext/stock/get_item_details.py b/erpnext/stock/get_item_details.py
index 33aceab0bf3..aa9750f7523 100644
--- a/erpnext/stock/get_item_details.py
+++ b/erpnext/stock/get_item_details.py
@@ -1269,6 +1269,10 @@ def get_item_price(
 			& (IfNull(ip.valid_upto, "2500-12-31") >= pctx.transaction_date)
 		)
 
+	# Final unique tiebreaker: rows tied on every sort key above (same valid_from/batch/uom/party)
+	# would otherwise be picked arbitrarily -- MariaDB and Postgres can differ. Pin the pick.
+	query = query.orderby(ip.name, order=frappe.qb.desc)
+
 	return query.run(as_dict=True)