iMovie for iOS terminates abnormally.

Occasionally iMovie for iPhone / iPad terminates abnormally.
I switched app without saving by tapping “Done” on upper left.

I watched Instagram.

Then I switched the app again and tap iMovie.

Boom!
iMovie came to an abnormal end.

I started iMovie again and found all changes were saved.
But you should tap “Done” to save your video safety when you switch the app.