eglinsky2012, Did you find any more information on what was needed to fix this issue?  We are also experiencing the same issue randomly and cannot find a root cause for it.  We are on WISM2 8.0.140 using 3500/3600 APs. Thanks!

Yes, I have this issue, too and recently it has gotten a lot worse.  The AP does not fail over to another wlc (which the backup is setup exactly the same).  An AP will loose some of their mappings (like 2 or 3 out of 4), but not the AP group or AP mo...