Fixed BOM value not updating on changing item (#9350)

diff --git a/erpnext/manufacturing/doctype/bom/bom.js b/erpnext/manufacturing/doctype/bom/bom.js
index 03e5390..83e0950 100644
--- a/erpnext/manufacturing/doctype/bom/bom.js
+++ b/erpnext/manufacturing/doctype/bom/bom.js
@@ -68,6 +68,10 @@
 			scrap_items = true;
 		}
 
+		if (child.bom_no) {
+			child.bom_no = '';
+		}
+
 		get_bom_material_detail(doc, cdt, cdn, scrap_items);
 	},
 })