Problem description
The startRecording() completion handler is never entered, even though the \"Allow screen recording in $AppName\" pop-up was show
I guess I found the answer myself. Please try this out and and confirm if it works:
My suspicion is that there is some bug in the used shared instance of the recorder which can only be reset when cleaning up the device RAM.
Edit: I also observed that this error only happens when I stop the running app with Xcode while the recording is in progress. If I put the app in the background or shut down the app with the iOS task manager, then this error does not appear when the app is started again.
Conclusion: DO NOT shut down your app using Xcode, while recording is running. If you use the iOS task manager instead then it will continue working properly and deliver the callbacks.
Edit 2: A bug report is filed and Apple answered that they are aware of this problem, working on it to solve it.