We’ve also been seeing issues with Game Center authentication for a few days. Telling users to restart device seems to resolve issue sometimes. Hope this gets fixed soon.

Same issue in iOS 15.7. We originally saw the issue in 15.6 and 16.0 betas, but it was fixed. Disappointing that there is this regression in 15.7.

We've started seeing the same in our apps. For users that are impacted by it, it seems to happen a lot.