Screen Rotation on 20.04 with Gnome 3.36 not working as expected

I have the following problem: Screen rotation works like a charm but there is an annoying problem:

When i try to open a video in fullscreen mode the screen orientation switches after about 2 seconds (happens in the browser (i.e. youtube) and also with the gnome video player)

So at first the orientation is correct (normal orientation) and after about 2 seconds it flips +180 degree - means upside down.And then it stays upside down as long as I am in full screen mode. When exiting the full-screen mode the orientiation becomes normal again.

I already tried to lock and unlock screen rotation in the gnome topbar. But the problem still exists.

...Besides I don't want to uninstall the automatic screen rotation sensors because it is working very nicely for all the other situations. Of course only if there is no other way to solve this problem.

Ubuntu 20.04 Gnome 3.36 Lenovo Thinkpad Yoga x380

thanks

Update:

I just tried to disable fractional scaling to the normal setup and the problem was solved by this. So the problem is only when fractional scaling is enabled...