Just tested on my two S21 Ultras. If you make a video full screen, the UI will crash and the lock screen will appear. Any app that doesn't leave full screen mode when the lock screen appears, like YouTube, will cause an endless loop that's pretty difficult to get out of.
I've already submitted a bug report but wanted to share here for awareness.
Please erase the device cache using steps below. Thank you very much for reporting the issue to us. We appreciate your contribution to the Beta community.
Turn off the device.
Press and hold the Volume Up key and the Side key.
When the Android logo displays, release both keys.
An 'Installing system update' message may show briefly before the Android Recovery menu options appear.
Press the Volume down key several times to highlight Wipe cache partition.
Press Side key to select.
Press the Volume down key to highlight Yes, then press the Side key to select.
When the process is complete, Reboot system now is highlighted.
