Warhammer Vermintide 2 - SSAO bugged?

I noticed some kind of film grain/noise, greasy effect and artifacts in the shadows of Vermintide 2. I tried turning all graphic options on and off until I found the source of it. It is SSAO! On medium everything seems fine, on high its really bad and on extreme its still there but much better (the effect on extreme is really hard to see in the video).