System is:
Manjaro 17.0.2 64Bit
Kernel Version 4.4.79
intel i7 6700
32GB RAM
NVidia GTX 1050Ti with driver Version 375.82 (OGL 4.5.0)
Happened also on earlier versions of kernel/driver/engine starting with the 2.0 branch of GZD.
Here's a shot of GZ running in OGL with doom.wad (Ultimate) at the end of E1M1:

A reference shot with brutalv20b-R3 in OGL/Software mode, as it appears on blood patches too. There's quite some Z-Fighting going on, but that's irrelevant for this...



Same happens in vanilla HACX again in OGL/Software


Also in Hexen...


It seems to be related to these other 2 threads:
viewtopic.php?f=7&t=57101
viewtopic.php?f=7&t=57108
My .ini files are attched in the zip file.
If there's more info I can provide, just let me know how. I more end user than coder, but I can figure stuff out...
