Door makes loud bump upon closure
It's a bit hard to say what is causing the noise without an onsite inspection. Why not just try to muffle it (unless you are concerned about a structural problem).

Consider small bumpers, either vinyl, cork or felt, something like these







These are all self-stick and any of them could be put on the top and/or bottom edge of the strike side of the door frame. The can be cut to fit and may eliminate or at least reduce the banging.