Late update on this: NOPE, still doesn’t work. I was wrong, monitor resolution has nothing to do with it. Apparently it’s FXAA!?? 
Turning it lower than HIGH, makes the issue re-appear. I didn’t experiment with any other scalability settings though. I have FXAA settings in my settings menu, which I’m changing through the console command node. That’s why I was able to catch it.
I even tried it in a new project, and it’s the same. Granted, i had to migrate many of my assets to the new project, so if it’s any of them causing it, i don’t know, but it’s not that many and it’s only stuff made in engine, nothing imported. I have no 3rd party plugins installed either.
At one point, I thought maybe it’s because I have a Persistent level + a streaming level loaded at the same time, and maybe Absolute World Position gets confused that way? But I tried it in a single level on its own, and same issue occurs.
Completeley lost here.