We integrated OIM 11gR2 with AD by using ICF based connector successfully. But when we try to lock AD account from AD process from user was not locking physically at AD. But all task history are showing successfully and not getting any error in OIM and connector server log.
I would say to you there is an issue between the connector jar files into OIM doing the tasks they suppose to do into AD. So, try to compare(size and files) of connector jar files between environments that you have maybe you can replace or restore couple of them. You should find some discrepancy between those.