Years ago an appliance repair person said the way to test seals is by using a dollar: Put a dollar in a door seal with just enough to hold on to. Close the door. The seal is tight if you can't pull it out, not tight enough if it slide out easily. I've been using this test for years and it works great.

I've found many MBZ doors are not quite evenly sealed all around a door opening.

Hope this helps.