GameCenter authentication returns false + Crash when using error string callback

Unity Version: 5.5.0f3
XCode Version: 8.2.1
iOS: 10

We recently updated to Unity 5.5, mainly for some bug fixes and the new GC Authentication Callback returning error strings.

However i seem to have problems authenticating now, it worked just fine before the update.

To make things simpler, i created a test scene with following code:

GameCenter authentication returns false + Crash when using error string callback