I've been struggling for a few of hours trying to get the GameCenter Multiplayer object working on two devices: iPhone 5 running iOS6.1, and iPod touch 4th gen running iOS6.0.
I bumped into quite a peculiar crash on the iPod touch that seems to somehow relate to GameCenter and list objects:
In frame 1, I do the GameCenter authentication and multiplayer match setup.
When the match is started, the game jumps to frame 2.
In frame 2, there are 60 list objects (yes, I need them all :)) - no events or any other objects (as I removed them when isolating the issue).
In frame 2, after a few seconds, iPod touch crashes every time.
At the moment of crashing, Xcode gives the following output: 2013-06-21 22:51:02.538 gamename[131:407b] CONNECTION INTERRUPTED
Before crashing Xcode says: <Info>: 22:50:38.027856 com.apple.AVConference: GKSConnSettings: set server { "gk-cdx" = "17.173.254.XXX:XXXX"; "gk-commnat-cohort" = "XX.XXX.XXX.XXX:XXXX"; etc... }
When I remove the list objects in frame 2, iPod touch does not crash anymore.
When I enter frame 2 without being signed in to GameCenter, the game does not crash on iPod touch, even with all the list objects.
On iPhone 5, I have not been able to reproduce the same crash. On iPod touch, it crashes every time.