My doors (metal rollup doors) our skeletal meshes (movable only), they have to be one mesh and the lighting is the same on both sides on the door (not introducing any crazy light there). When I bake the scene with cpu lightmass the doors (all skeletal meshes) look really bad, which is strange because this never happened before (UE4). However if I bake using the gpu lightmass I get the better result I would expect. Just sucks that you have to have a video card supporting Raytracing to bake lights.