Bad directing in the Fifth Anniversary episode
During the scene where they are in the mobile home the camera pulls back too far and you can see where the floor of the set ends in a lot of shots.
Also when the set tilts there are a few shots where you can see the top of the set wall ends.
But pulling the camera back too far ruins the illusion that they are supposed to be in a tiny mobile home. I also noticed that the side walls are angled.