BTW, on my last flight, I used my app boarding pass. Was looking at the boarding pass QR code 1 second before advancing to the scanner. Put my cell phone on the reader and.... nothing. Tilted my phone to observe, and somehow, the app had reverted to the home screen. Boomer moment? Perhaps. Everyone had to wait an extra 7 seconds for me to call up again my e-boarding pass.

The printed boarding pass never reverts to a different screen.