I can't remember exactly, but I think it started to happen from revolver update. After doing full HDR or even just a full final compile (doesn't matter really) in some areas a very dark shadow appears:
And I would like to know, what causes these dark "stains" and if there is a way to fix them without using customly made light entities?
Also, I found another things like:
In the middle, the shadow is accurate but on the right lower part of the arch it is just a pure black colour. Is there a way to fix it, if so, how?