Artifacts in glmark2 with three T1000 cards and BaseMosaic


I’m trying to build video-wall system with Asus WS X299 SAGE motherboard and three T1000 cards (4x3 video wall, 7680 x 3240 with 12 Full HD monitors).
Ubuntu 20.04 LTS based system.
There are different issues in the process and here is one - I see strange artifacts when trying to use some testing with glmark2 2021.02:

This is with 525.105.17 driver. Tried 470.182.03 and older driver had even more problems with displaying content.

Is this something that can be fixed with some configuration or this is sign of broken hardware?

There is no such problem when I run in small window 1280x800:

nvidia-bug-report.log.gz (1.3 MB)

Please run as root and attach the resulting nvidia-bug-report.log.gz file to your post.

Please see attached.
As I found now - on monitors we have correct image.
Artifacts appeared in screenshots obtained with xwd tool.