Seeing the same issue for smoke and fire particle effects. Created an mesa issue for it https://gitlab.freedesktop.org/mesa/mesa/-/issues/11864. This might be an vkd3d-proton issue though as it is also seen on AMDVLK, @HansKristian-Work.
I've not had a chance to test it on Windows yet.
proton experimentalx1 2023-11
Some particle effects around the ship seem to have weird blocky artifacts that I have verified do not happen on Windows, however I also captured a issue I didn't mean to with exploding geometry but this is something that happens with the game a lot even on Windows and might not be due to vkd3d but maybe worth noting, however I have never seen it in the pause screen until now but it seems to be known issue with this game
Software information
Starfield Beta 1.8.84, but tested with same result on at least 2 patches back. Also running at the ultra preset at 1080p
System information
Log files
steam-1716740.log (note this log doesn't include the exploding geometry)
Screenshots
Video demonstrating the issue, also unintended exploding geometry bug that likely is unrelated to vkd3d
https://youtu.be/L81P18uYKQk