I'm facing the same issue. Hopefully, it will be fixed soon.

Does anyone else have this issue right now? Almost half of our active subscribers have just disappeared.

while (WidgetsBinding.instance.lifecycleState != AppLifecycleState.resumed) { await Future.delayed(Duration(milliseconds: 400)); } To check if the TestFlight window has disappeared before triggering the ATT prompt. After this, the app update has been approved.

Change 8.0 to 11.0 worked for me