I had this problem now a few times, after a while the display bugs out and scrolls uncontrollably up or down, even if i just hold my finger still pointed at the middle of the screen. For example i use the chrome ap and scroll down, suddenly it scrolls by itself way up and even opens links or pictures i didn’t want to open.
It happens suddenly, becomes stronger with time and even after rebooting it doesn’t allways go away.
It usually happens when i used the phone for a while, i assume it’s connected to heating up.
At some point certain aps become useless (my Deutsch Bahn ap at one point, when i wanted to show my train ticket, unfortunately wouldn’t work properly anymore)