Weird AO/shadow problem

Im trying to do a grayscale render with the render setup parameters. I already did a couple of them in the last weeks, but this last one has the jacket having glowing spots for some reason. I think its about Ambiant Occlusion or something, but none are activated so I do not know where to search. The only difference I did since the last render before this one is tweaking some texture colors and adding a rig