We are seeing crashes on iOS 15 (unreproducible on iOS 14) being reported without any Termination Reason or Code.
I've read several similar questions but don't see a general solution to the problem, and most of them are crashes from the Xcode Crashes Organizer so I'm not sure if this is a bug on the TestFlight side.
These all happened right after the user backgrounds the app.
crashlog1.crash
crashlog2.crash