Sounds familiar. I'm pretty sure people have had something like this going on for at least a couple patches. Though the descriptions vary, I recall reading it in responses to a couple patch/hotfix replies going back to last year maybe? Though these can be hard to search, you might end up with solutions from Early Access or older builds or whatever. You might try the larian discord since it's more active than these boards. Peeps do tend to show back up whenever a new patch drops, but it's kinda slow days on the forums.
For me the issue was more boiler plate. Basically any dialogue that goes into cutscene closeup zoom, I'll get that little split second delay while the textures load. So you know any merchant or NPC, they'll initially look like some monstrosity or with weird glows and aliasing snafus until it loads. I just assumed it was DLSS upscaling weirdness, since it's so consistent, but I think others pointed to the level cache needing to be cleared or things in the graphics settings depending on how long ago.
At one point somebody mentioned it in a thread somewhere with a very technical description of what's happening and noting which patch and I think even the line of code that got changed or whatever, but I can't remember when. I almost wrote it down, cause it had the verbiage and the name of the exact visual issue I was experiencing. But the context was an offhand gripe among other feedback in the replies, like grumbling that the issue was introduced post Launch, and still not resolved by whatever patch had just dropped hehe. I just sorta filed it away as something above my head that would probably get sorted eventually. That was a while ago though, several months. Maybe it's in the news section under one the patch/hotfixes but there are quite a few?
On discord you might catch someone who knows how to parse or debug your graphic settings, otherwise it's probably like deciphering hieroglyphics with no rosetta stone. I imagine the first Q will be whether or not it happens to you in a unmodded game too?
Not sure, hopefully you can get it sorted. Most my runs now just involve spamming the spacebar and skip dialogues at a frenetic clip, so I barely notice now. My headcanon is that all my Durges probably really needs to visit the ophthalmologist, just to get their one good eye checked out, but of course all the healers in Act I are a bit hit or miss, so I'm still foot draggin on that front. Best of luck though, let us know if you figured out what it was, or how to fix it
