diff --git a/erpnext/manufacturing/doctype/production_plan/production_plan.py b/erpnext/manufacturing/doctype/production_plan/production_plan.py
index b942842d1ce7eab5898f50837c1b051c6eb47665..fdef8fe61bd505fb8922cdad2dbd1e8553a781aa 100644
--- a/erpnext/manufacturing/doctype/production_plan/production_plan.py
+++ b/erpnext/manufacturing/doctype/production_plan/production_plan.py
@@ -652,7 +652,10 @@ class ProductionPlan(Document):
 				"project": self.project,
 			}
 
-			key = (d.item_code, d.sales_order, d.warehouse)
+			key = (d.item_code, d.sales_order, d.sales_order_item, d.warehouse)
+			if self.combine_items:
+				key = (d.item_code, d.sales_order, d.warehouse)
+
 			if not d.sales_order:
 				key = (d.name, d.item_code, d.warehouse)