My app record audio in background mode. Sometimes the app crashes (I still don't know why) but then it restarts by the system itself. Before being closed, I pause audio recording (inside applicationWillTerminate) and I use play function, after the app reopened, inside a sync function that runs in my app every minute.
On my test mobile (Iphone 5s, IOS 13.2.3), the app never crashes (to simulate I have to close the app manually) and always works resume the audio recording in the way that I have described. In the users' mobile (several Iphone models, but higher than 5c) I see in the log file that the app could not resume audio recording after the app has crashed.
Sorry because I don't know much more information for now, but if someone could help understand why it is happening, I would be very grateful.