Ok thanks to the generous help of
Don Peste and some French Fallout forum I could test 2.0.1. and 1.5.1 of the UAP patch.
In case anyone cares:
The bug described by
Bester is not new to 2.0.2., it already occurs in 2.0.1. at least. It occurs when you select the hardware renderer in the config of the high res patch. With the software renderer, the problem doesn't seem to occur.
In 1.5.1 the problem doesnt occur at all, no matter which setting is selected. But hardware mode is slow and unresponsive for me.
Also, in the 2.x versions of the UAP, something was changed in the high res patch that completely fucks up the videos in the game for me, while they run perfectly fine in 1.5.1. The new ddraw.dll?
EDIT: Can confirm, replacing the ddraw.dll in 2.0.2 with the old version from 1.5.1. solved the fucked up videos for me, and also the bug described by bester doesn't occur anymore even in hardware mode.
However, hardware mode is slow and unresponsive (especially scrolling during combat), just as it was in 1.5.1.
So I use software mode by default anyway.
I think the problem is that with 2.x, Drog included the latest experimental test release of DDrawCompat with the UAP/high res patch, while 1.5.1. used the previous stable version
DDrawCompat v0.2.1. So just download it and put in in your highres -> files folder if the latest version gives you trouble.
So there you have it.