App crashes when started from TestFlight and closed again

We see a strange problem with TestFlight.

Our app just works fine, but every time the user closes it (swipes it out), a crash message appears after about 10 seconds. Even if I share the crash report with TestFlight, it only includes a simple JSON file, but no detailed description what happened, so I have no clue what is going on.

The app does not show crash messages if opened from Xcode or from the App Store. Only TestFlight seems to be affected.

the complete error is attached to this message




I think this is the core problem:
[application<com.my.app>:1447] failed to terminate gracefully after 10.0s

I noticed that the problem appears less likely when you bring the application to the background first and then - after a while - close it completely. If you do close it directly - by flicking it out of the screen - the error message appears nearly every time.

Any way to solve this?

I got the same problem with the release app on Testflight with [Unity-2018.4.10f1] but it just crashed when I kill the app in landscape mode, no crash if I kill the app in portrait mode. If I build the app directly into the phone via Xcode, the crash also won't happen.

App crashes when started from TestFlight and closed again
 
 
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