I have observed a lot of times this issue, but never read about it. Using high quality lightmaps, with high resolution, quality preset, enough pool size, no compression, on a 2080 ti, etc… for ArchViz, I usually notice some wird shadows over the distance, like low res, buth whe I move towards them, they “load” and they will be shown correctly, even if I go far again. So, it’s something like they don’t load at all when I open the map or spawn my pawn, even if I wait for minutes.
Have tried with 4.23-4.26, with GPU and CPU lightmass, with the same result.
Examples (sorry, wasn’t able to post the images directly. This forum is a pain):