diff --git a/erpnext/controllers/status_updater.py b/erpnext/controllers/status_updater.py
index 0dc9878..9feac78 100644
--- a/erpnext/controllers/status_updater.py
+++ b/erpnext/controllers/status_updater.py
@@ -255,7 +255,7 @@
 				args['second_source_condition'] = """ + ifnull((select sum(%(second_source_field)s)
 					from `tab%(second_source_dt)s`
 					where `%(second_join_field)s`="%(detail_id)s"
-					and (`tab%(second_source_dt)s`.docstatus=1) %(second_source_extra_cond)s), 0) """ % args
+					and (`tab%(second_source_dt)s`.docstatus=1) %(second_source_extra_cond)s FOR UPDATE), 0)""" % args
 
 			if args['detail_id']:
 				if not args.get("extra_cond"): args["extra_cond"] = ""