fix(manufacturing): case-insensitive batch_no filter in Cost of Poor Quality report

The report's batch_no filter used an exact `==`, which is case-sensitive on Postgres -- a
differently-cased batch_no missed Job Cards that MariaDB (case-insensitive collation)
matches. Add a dedicated batch_no branch wrapping both sides in Lower() (keeping the exact
match, not a substring like serial_no): MariaDB result is unchanged, Postgres now matches.

erpnext/manufacturing/report/cost_of_poor_quality_report/cost_of_poor_quality_report.py

@@ -3,6 +3,8 @@
 
 import frappe
 from frappe import _
+from frappe.query_builder.functions import Lower
+from frappe.utils import cstr
 
 
 def execute(filters=None):
@@ -63,6 +65,9 @@ def append_filters(query, report_filters, operations, job_card):
 		if report_filters.get(field):
 			if field == "serial_no":
 				query = query.where(job_card[field].like(f"%{report_filters.get(field)}%"))
+			elif field == "batch_no":
+				# Lower() both sides: exact match stays case-insensitive on Postgres as it is on MariaDB
+				query = query.where(Lower(job_card[field]) == cstr(report_filters.get(field)).lower())
 			elif field == "operation":
 				query = query.where(job_card[field].isin(operations))
 			else:

erpnext/manufacturing/report/cost_of_poor_quality_report/test_cost_of_poor_quality_report.py

@@ -0,0 +1,65 @@
+# Copyright (c) 2026, Frappe Technologies Pvt. Ltd. and Contributors
+# See license.txt
+
+import frappe
+from frappe.utils import add_to_date, now
+
+from erpnext.manufacturing.doctype.job_card.mapper import make_corrective_job_card
+from erpnext.manufacturing.doctype.work_order.test_work_order import make_wo_order_test_record
+from erpnext.manufacturing.report.cost_of_poor_quality_report.cost_of_poor_quality_report import execute
+from erpnext.stock.doctype.stock_entry.stock_entry_utils import make_stock_entry
+from erpnext.tests.utils import ERPNextTestSuite
+
+
+class TestCostOfPoorQualityReport(ERPNextTestSuite):
+	def setUp(self):
+		self.load_test_records("BOM")
+		# BOM with operations for _Test FG Item 2, so submitting the work order creates Job Cards
+		bom = frappe.copy_doc(self.globalTestRecords["BOM"][2])
+		bom.set_rate_of_sub_assembly_item_based_on_bom = 0
+		bom.rm_cost_as_per = "Valuation Rate"
+		bom.items[0].uom = "_Test UOM 1"
+		bom.items[0].conversion_factor = 5
+		bom.insert(ignore_if_duplicate=True)
+
+	def test_batch_no_filter_is_case_insensitive(self):
+		# The report's batch_no filter used an exact `==`, which is case-sensitive on Postgres -- a
+		# differently-cased batch_no would miss job cards that MariaDB (case-insensitive collation)
+		# matches. Lower() both sides keeps MariaDB unchanged and makes Postgres match too.
+		wo = make_wo_order_test_record(item="_Test FG Item 2", qty=2, transfer_material_against="Work Order")
+		for item in wo.required_items:
+			make_stock_entry(
+				item_code=item.item_code,
+				target=item.source_warehouse,
+				qty=item.required_qty * 2,
+				basic_rate=100,
+			)
+
+		job_card = frappe.get_last_doc("Job Card", {"work_order": wo.name})
+		job_card.append(
+			"time_logs", {"from_time": now(), "to_time": add_to_date(now(), hours=1), "completed_qty": 2}
+		)
+		job_card.submit()
+
+		corrective_op = frappe.get_doc(
+			doctype="Operation", is_corrective_operation=1, name=frappe.generate_hash()
+		).insert()
+		corrective_jc = make_corrective_job_card(
+			job_card.name, operation=corrective_op.name, for_operation=job_card.operation
+		)
+		corrective_jc.hour_rate = 100
+		corrective_jc.insert()
+		corrective_jc.append(
+			"time_logs",
+			{
+				"from_time": add_to_date(now(), hours=2),
+				"to_time": add_to_date(now(), hours=2, minutes=30),
+				"completed_qty": 2,
+			},
+		)
+		corrective_jc.submit()
+		# store an uppercase batch_no; the report is then filtered with a lowercase value
+		corrective_jc.db_set("batch_no", "TESTCOPQBATCH")
+
+		_columns, data = execute(frappe._dict({"batch_no": "testcopqbatch"}))
+		self.assertTrue(any(row.get("name") == corrective_jc.name for row in data))