The exception code "0xbaadca11" indicates that your app was killled for failing to report a CallKit call in response to a PushKit notificaiton. That should have been clear in the crash log, but this particular requirement is implemented through multiple code paths and it looks like this one isn't as clear as the others. For more details on the new requirement, take a look at:
Developer Technical Support
On iOS 13 we no longer use PushKit notifications.
We are guessing this may happen when someone upgrades to iOS 13 from an earlier version of iOS and the device had registered for PushKit notifications previously. It seems it would be possible for that device to receive a PushKit notification from the old registration. In our case the app would clear that registration once the app is loaded by the user and it shouldn't happen again.
Do you think this is a reasonable guess on what is happening?
Did your fix resolve the crash?
And how did you clear the VOIP registration? By simply setting the PKPushRegistry's delegate to nil?
We are seeing the same crash on upgrade from our iOS 12 client where we registered for PushKit to iOS 13 client where we don't.