GameCenter crash only in release build

The app runs great from XCode, no errors.

I make an archive. I make an ad-hoc build, run the IPA, no errors.

I use the same archive to upload to the app store. It crashes on GameCenter login. The report is in the image below. (String_Concat_m2596509543)


Any ideas what may be going on here?

Additional info: on the first release of the app, I forgot to enable GameCenter Capabilities (it used to be on by default). It ran fine from XCode, but the ad-hoc IPA crashed. In this version, it is enabled, and the IPA works.

I may have figured it out.

When calling Social.localUser.Authenticate, you have 2 possible callback methods (both work on Android and in XCode), according to the documentation:

public void Authenticate(Action<bool> callback);
public void Authenticate(Action<bool,string> callback);

Using the 2nd will cause the crash when released on the App Store if authentication is successful. Using the first works without any problems.