diff --git a/erpnext/controllers/stock_controller.py b/erpnext/controllers/stock_controller.py
index 2cdf076de2f..d21fcacb4e0 100644
--- a/erpnext/controllers/stock_controller.py
+++ b/erpnext/controllers/stock_controller.py
@@ -524,7 +524,13 @@ class StockController(AccountsController):
 			):
 				reference_ids.append(row.get(field))
 
-			if table_name == "packed_items" and row.get("parent_detail_docname"):
+			# Packed items with serial / batch fields (e.g. delivered before v15) can have no bundle
+			# to return against, make_bundle_using_old_serial_batch_fields handles them
+			if (
+				table_name == "packed_items"
+				and row.get("parent_detail_docname")
+				and not (row.serial_no or row.batch_no)
+			):
 				parent_rows = self.get("items", {"name": row.parent_detail_docname}) or []
 				for d in parent_rows:
 					if d.get(field) and not d.get(bundle_field):
diff --git a/erpnext/stock/doctype/delivery_note/test_delivery_note.py b/erpnext/stock/doctype/delivery_note/test_delivery_note.py
index 7c649325d83..b93a60c8349 100644
--- a/erpnext/stock/doctype/delivery_note/test_delivery_note.py
+++ b/erpnext/stock/doctype/delivery_note/test_delivery_note.py
@@ -3316,6 +3316,50 @@ class TestDeliveryNote(FrappeTestCase):
 						serial_batch_map[row.item_code].batch_no_valuation[entry.batch_no],
 					)
 
+	def test_sales_return_for_product_bundle_with_legacy_serial_nos(self):
+		bundle_item = make_item("_Packed Legacy Bundle Item", {"is_stock_item": 0}).name
+		stock_item = make_item("_Packed Legacy Stock Item", {"is_stock_item": 1}).name
+		serial_items = [
+			make_item(
+				f"_Packed Legacy Serial Item {i}",
+				{"is_stock_item": 1, "has_serial_no": 1, "serial_no_series": f"SN-PACKED-LEGACY-{i}-.#####"},
+			).name
+			for i in (1, 2)
+		]
+		for item_code in [stock_item, *serial_items]:
+			make_stock_entry(item=item_code, target="_Test Warehouse - _TC", qty=2, rate=100)
+		make_product_bundle(bundle_item, [stock_item, *serial_items])
+
+		dn = create_delivery_note(item_code=bundle_item, warehouse="_Test Warehouse - _TC", qty=2)
+		dn.reload()
+
+		# Delivery notes from before v15 have serial nos in the packed items without a bundle
+		delivered_serial_nos = {}
+		for packed_item in dn.packed_items:
+			if packed_item.item_code not in serial_items:
+				continue
+
+			serial_nos = get_serial_nos_from_bundle(packed_item.serial_and_batch_bundle)
+			delivered_serial_nos[packed_item.item_code] = sorted(serial_nos)
+			legacy_values = {"serial_no": "\n".join(serial_nos), "serial_and_batch_bundle": None}
+			packed_item.db_set(legacy_values)
+			frappe.db.set_value(
+				"Stock Ledger Entry",
+				{"voucher_no": dn.name, "item_code": packed_item.item_code},
+				legacy_values,
+			)
+
+		return_dn = make_sales_return(dn.name)
+		return_dn.submit()
+		return_dn.reload()
+
+		returned_serial_nos = {
+			row.item_code: sorted(get_serial_nos_from_bundle(row.serial_and_batch_bundle))
+			for row in return_dn.packed_items
+			if row.item_code in serial_items
+		}
+		self.assertEqual(returned_serial_nos, delivered_serial_nos)
+
 	@change_settings("Stock Settings", {"allow_negative_stock": 0, "enable_stock_reservation": 1})
 	def test_partial_delivery_note_against_reserved_stock(self):
 		from erpnext.stock.doctype.stock_reservation_entry.stock_reservation_entry import (
diff --git a/erpnext/stock/doctype/packed_item/packed_item.py b/erpnext/stock/doctype/packed_item/packed_item.py
index e742c8e703e..19b2d734cfd 100644
--- a/erpnext/stock/doctype/packed_item/packed_item.py
+++ b/erpnext/stock/doctype/packed_item/packed_item.py
@@ -107,13 +107,16 @@ def get_indexed_packed_items_table(doc):
 	Use: to quickly retrieve/check if row existed in table instead of looping n times.
 	A component repeated on a bundle shares one key, so rows are kept as a list and
 	consumed per occurrence rather than collapsed onto a single row.
+
+	A new doc (e.g. mapped) has no link to its item rows yet, so its packed rows are
+	consumed in order per parent item and component.
 	"""
 	indexed_table = {}
 	for packed_item in doc.get("packed_items"):
 		key = (
 			packed_item.parent_item,
 			packed_item.item_code,
-			packed_item.idx if doc.is_new() else packed_item.parent_detail_docname,
+			None if doc.is_new() else packed_item.parent_detail_docname,
 		)
 
 		indexed_table.setdefault(key, []).append(packed_item)
@@ -179,7 +182,7 @@ def add_packed_item_row(doc, packing_item, main_item_row, packed_items_table, re
 	key = (
 		main_item_row.item_code,
 		packing_item.item_code,
-		main_item_row.idx if doc.is_new() else main_item_row.name,
+		None if doc.is_new() else main_item_row.name,
 	)
 	# a component repeated on the bundle shares one key; consume stale rows in order so
 	# each occurrence keeps its own packed row instead of overwriting a single one