Chris
]]>According to the release blog you could have a problem with both SQL2012 SP2 CU3 and CU4 if you have alwayson availability groups with NOT SYNCHRONIZING being reported. See http://blogs.msdn.com/b/sqlreleaseservices/archive/2015/01/21/alwayson-availability-groups-may-be-reported-as-not-synchronizing-after-you-apply-sql2012-sp2-cu3-or-sql2012-sp2-cu4-or-sql2014-cu5.aspx for full details.
Same goes for SQL2014 CU5.
Chris
]]>