My dad hit one a few days ago, complained he couldn't restart his phone. I proceeded to watch him hold down the volume and power button to get the prompt to shutdown/reboot. Upon clicking, it did nothing. So I tried it then, still nothing. Realized at this point that the device had lockscreen locked. After unlocking the screen and repeating this it rebooted fine. (My first gut reaction was 'can't you just hold power button to get the reboot screen?', but nope that pops up some google assistant crap instead, so now he has to juggle not having it screenshot each time he needs to shut it off or restart it)