Hm. Could be a shader problem or because I use an older version of the patch. I'll run some tests and see if I can find a fix.
Edit: It works on the newer version of the patch. If haven't already tries, redownload the files and then extract them directly into the iw.39 folder. Also turn off Shader Warming under graphics settings. That might help if you're running on lower end hardware. This sounds obvious, but be sure to click Replace All if you're manually going to extract the files.
I would send a copy of the version of the patch that I run, but I don't know if BoneCrusher is fine with that, considering I'm using the version that was created when he deleted his discord server and privated all his YT Videos. The likeliness of even getting an answer from him would be below 0.
Other than that, these are the graphics settings that I found work easiest for this patch.
plutonium-bootstrapper-win32 Screenshot 2023.09.09 - 01.55.41.78.png