I may also have found a genuine new bug. Switched the screen on and swiped left to home screen. Did not get asked for the password, but did not pay much attention to that because it may have been before the timeout. But then, instead of the home screen, I got blackness. Swiping back to events seemed to work but swiping to home screen again resulted in the same thing. Launcher did not work, basically nothing worked. I switched the screen of using the power button, then on again and this time I was greeted with a password prompt as expected and everything worked as normal.

It looks like some race condition to me. I must have activated the screen just around the time when the timeout would kick in.