Team wolf: When you use very thin walls the "shadow" depth buffer will not be preside enoff to see the wall , Lee has improved the depth buffer in the next "public preview" coming in a few days , it might help in this case, well at least it will allow you to have smaller geometry and still have shadows.
When using thick walls you still get the problem: When a shadow depth buffer is rendered using a camera , it ONLY render the back faces of the models ( your wall ) , so perhaps you have some geometry going wrong ? , could you try to place a wall from the default GG media and see if that will block the shadow ? , if so perhaps you have something inverted in you model ? , if your using standard media please share what model your using
Only after prebake: could you try to see if there is any collision when this happens , try to see if you can walk through that wall when you see the shadow ? , Lee fixed some stuff when loading the lightmapped version of the object , like normals ... so perhaps its just something like this , this has been fixed in the new "Public Preview" version coming in a few days , perhaps this release will fix it
best regards Preben Eriksen,