Mine "leaks" around around the top door corners, and door center. (different brand). I was told as the residue builds up from smoking, the leaking will diminish. It has to some degree. I bought it used and did not realistically expect it to perform as new (maybe I did a little).
3M makes a high temperature stainless steel tape that I suppose could be used to "tighten up the seal" somewhat on the door. I would look at the staining around the interior door perimeter and if minimal, ignore it. But you could always give it a try, concentrating only on the stained area. The clean area would indicate no leak. This might work, might not. Just be sure to cut it no wider than the clean border area where the door meets the cabinet, and no longer than the stained ares.
Have you contacted Steve? I would do that first.