unity3d occlusion culling error Failed getting triangles

Hi, I simply try to build occlusion culling for my scene but I always get this error in the console
“Failed getting triangles. Submesh index is out of bounds.”
until unity shows me a error and than it closes. I have absolutly no idea what it colud be :confused:

Screenshot

Log

create new scene, new gameobject, bake lighting, see if problem persist