Issue
AD directories are no longer synchronized.
When modifying an AD directory attribute (e.g. 2008r2), you get the message:
The FSMO role ownership could not be verified because its directory partition has not replicated successfully with at least one replication partner.
Solution
Force AD directory synchronization by running the windows command Repadmin /syncall DC_name /APed on a DC.
See also
http://blogs.technet.com/b/askds/archive/2009/07/01/getting-over-replmon.aspx