We are investigating a Game Center authentication issue that appears to affect some devices consistently. Symptoms: Game Center authentication initiated from our app does not complete. The GKLocalPlayer authentication flow does not recover during the session. The issue is not limited to our app: on affected devices, the Game Center section in the iOS/iPadOS Settings app also fails to load. The Games app also fails to load. After a device restart, Game Center may work once, but then becomes unavailable again and further authentication attempts fail. We have reproduced this on iPadOS 26.5. In addition, our analytics show an unusually high percentage of unfinished Game Center authentication attempts on this OS version. We have also received individual reports from users on other devices/OS versions. Given that the Game Center Settings screen and the Games app are also affected, this appears to be a system-level Game Center availability problem rather than an issue isolated to our application. There is a description of a similar problem https://developer.apple.com/forums/thread/787749 But it belongs to beta testing and is marked as fixed.