I checked my log yesterday for an issue not related to this one and saw that aprox. every second I get a message like this: Sep 6 10:54:32 my-mac.local md5: BUG in libdispatch: 12E55 - 1879 - ...
I had some trouble with my wifi connection so I figured, I could switch on logging for airport via sudo /System/Library/PrivateFrameworks/Apple80211.framework/Versions/Current/Resources/airport debug ...
After upgrading to Mountain Lion I have noticed this message being flooded into my system console: AppleIDAuthAgent: SERVER Removing certificate for Apple ID "...@???.??" dsID="XXXXX" because it ...