Horizontal lines on screen when wireless charging

Hi!

I noticed that when charging my iPhone 12 wirelessly, horizontal lines are visible when I am on a white background.

They appear to flicker (move up/down) and I can't capture them with a camera.

This does not happen when charging with a cable.

I already tried turning the phone off and on again. Also I have tried different wireless chargers. An iphone xs does not have this problem and I tried with the same wireless chargers.

Any idea why this happens?