On my s21 Ultra, I’m having an issue where when I unlock the device or turn the screen on, the device will vibrate anywhere between 2 and 15 times in a very rapidly (within 1-4 seconds, depending on how many times in decided to vibrate that time).
It doesn’t do it every time I unlock. It seems random. I had recently got a new case and thought that was the culprit, but confirmed it’s not with both a different case or no case – still happening.
I’m also noticing occasional spurts of haptic feedback when I’m just looking at the screen with no touch input.
Once, when the on screen keyboard was up when it happened, the keyboard fluttered up and down / on and off with these vibrations, leading me to think it’s the screen believing it’s being pressed.
I’ve cleaned the screen thoroughly. There are no cracks in it. I have no screen protector. I’ve also looked for anything lodged between the glass edge and frame of the phone, thinking something there could be causing inputs, but finding nothing.
I installed Nice Grab from the Galaxy Store, however it’s not capturing these vibrations. Only actual app related vibration notifications. I also uninstalled third party launchers, just in case, but that didn’t change anything.
Any thoughts what else could be the cause asides from hardware fault?