diff --git a/erpnext/manufacturing/doctype/production_plan/production_plan.js b/erpnext/manufacturing/doctype/production_plan/production_plan.js
index 5b4ef2339265..aba213ebca41 100644
--- a/erpnext/manufacturing/doctype/production_plan/production_plan.js
+++ b/erpnext/manufacturing/doctype/production_plan/production_plan.js
@@ -277,7 +277,7 @@ frappe.ui.form.on("Production Plan", {
 		frm.clear_table("prod_plan_references");
 
 		frappe.call({
-			method: "get_items",
+			method: "combine_so_items",
 			freeze: true,
 			doc: frm.doc,
 			callback: function () {
diff --git a/erpnext/manufacturing/doctype/production_plan/production_plan.py b/erpnext/manufacturing/doctype/production_plan/production_plan.py
index 7d3aa000c870..3f82a75d3020 100644
--- a/erpnext/manufacturing/doctype/production_plan/production_plan.py
+++ b/erpnext/manufacturing/doctype/production_plan/production_plan.py
@@ -269,6 +269,31 @@ def add_mr_in_table(self, pending_mr):
 				{"material_request": data.name, "material_request_date": data.transaction_date},
 			)
 
+	@frappe.whitelist()
+	def combine_so_items(self):
+		if self.combine_items and self.po_items and len(self.po_items) > 0:
+			items = []
+			for row in self.po_items:
+				items.append(
+					frappe._dict(
+						{
+							"parent": row.sales_order,
+							"item_code": row.item_code,
+							"warehouse": row.warehouse,
+							"qty": row.pending_qty,
+							"pending_qty": row.pending_qty,
+							"conversion_factor": 1.0,
+							"description": row.description,
+							"bom_no": row.bom_no,
+						}
+					)
+				)
+
+			self.set("po_items", [])
+			self.add_items(items)
+		else:
+			self.get_items()
+
 	@frappe.whitelist()
 	def get_items(self):
 		self.set("po_items", [])
@@ -435,24 +460,28 @@ def add_items(self, items):
 
 			item_details = get_item_details(data.item_code, throw=False)
 			if self.combine_items:
-				if item_details.bom_no in refs:
-					refs[item_details.bom_no]["so_details"].append(
+				bom_no = item_details.bom_no
+				if data.get("bom_no"):
+					bom_no = data.get("bom_no")
+
+				if bom_no in refs:
+					refs[bom_no]["so_details"].append(
 						{"sales_order": data.parent, "sales_order_item": data.name, "qty": data.pending_qty}
 					)
-					refs[item_details.bom_no]["qty"] += data.pending_qty
+					refs[bom_no]["qty"] += data.pending_qty
 					continue
 
 				else:
-					refs[item_details.bom_no] = {
+					refs[bom_no] = {
 						"qty": data.pending_qty,
 						"po_item_ref": data.name,
 						"so_details": [],
 					}
-					refs[item_details.bom_no]["so_details"].append(
+					refs[bom_no]["so_details"].append(
 						{"sales_order": data.parent, "sales_order_item": data.name, "qty": data.pending_qty}
 					)
 
-			bom_no = data.bom_no or item_details and item_details.bom_no or ""
+			bom_no = data.bom_no or item_details and item_details.get("bom_no") or ""
 			if not bom_no:
 				continue