DFAO causing blotches on surfaces - related to glass material?

hi Everyone,

whenever I have enabled DFAO, everything outdoors looks better of course, but I keep getting some kind of strange blotchiness on certain areas of my building - I am quite confident in the light maps not being an issue, and I noticed that if I move the wall or move the windows (as in a transparent material) away from each other, the blotchiness goes away - is my observation correct, and if so, what can be done? is there a glass material that doesn’t cause this? its not happening on the other windows, so if its not the glass, what else could cause this? I have this blotchiness somewhere on my buildings every single time I use DFAO.