fix: Added patch and fallback code to prevent future issues similiar to helpdesk ticket 28246

(cherry picked from commit 65dc3505c4)

# Conflicts:
#	erpnext/patches.txt

erpnext/controllers/subcontracting_controller.py

@@ -103,6 +103,16 @@ class SubcontractingController(StockController):
 						_("Row {0}: Item {1} must be a subcontracted item.").format(item.idx, item.item_name)
 					)
 
+				if (
+					not item.sc_conversion_factor
+				):  # this condition will only be true if user has recently updated from develop branch
+					service_item_qty = frappe.get_value(
+						"Subcontracting Order Service Item",
+						filters={"purchase_order_item": item.purchase_order_item, "parent": self.name},
+						fieldname=["qty"],
+					)
+					item.sc_conversion_factor = service_item_qty / item.qty
+
 				if (
 					self.doctype not in "Subcontracting Receipt"
 					and item.qty