Touchscreen issues

Sometimes i can’t work with the iPad and the Apple Pencil because of touchscreen issues. I cant really explain it with words so I attached a picture (unfortunately adding videos is not possible). When I am drawing or writing with the pencil the iPad breaks my lines and draws horizontal and vertical lines all over the screen. I realised it happens more often when I use graphic apps and the iPad is getting hot, but I also had the issue while just taking notes in class. This happens when my handpalm is in the corner of the display. So it seems that the touchscreen is not able ignore my handpalm which is a main feature for working with illustrations on a tablet.

is that a common issue? Is there a way to solve it? Should I get in touch with support?

edit: in the picture I was just drawing a wave on the note taking App notability.this is an extreme example. Often it is more like breaking a one-line word into several lines and dots. Still annoying.