Continuity mistake: In "The Thing and I": After the kids have found Hugo in the attic, when Marge and Homer return home, both front door knobs (inside and outside) do not have backplates, but once Hugo escapes both door knobs have backplates. The two backplates vanish and reappear repeatedly in following shots. It's funny because when they leave to search for Hugo, Homer shuts the door with no backplates, but then Bart uses a key in the backplate to lock The Front door.
Continuity mistake: In 'The Genesis Tub,' Lisa sits on a tooth-throne in the tub, which has red cloth draped over the arms with gold tassels around the edge. However when Bart comes to take the tub, Lisa stands up on the throne and yells "Bart, no!" In this shot the tassels are gone. (00:17:45)
Continuity mistake: In 'The Thing and I' when Homer and Marge return from driving around in the rain, there is no doorknocker on the door. Then in the shot where Hugo escapes, we see the door open with red scratches on it, and there is a doorknocker. Then later when everyone leaves to find Hugo, it's gone again. (00:02:40 - 00:04:55)
Continuity mistake: In "Citizen Kang", when Homer pulls off the masks off the fake Clinton and Dole at the White House, the two transform into aliens and you can see Homer is between them. In the next shot, Homer is missing, and in the shot after that, he is back again.
Continuity mistake: In Citizen Kang, when Kang and Kodos (as Clinton and Dole) are speaking to the man from the Democratic National Committee, you can see the building in front of them has a plant outside and there are shades on the windows. But when Homer appears in the next shot, the plant and shades have gone.
Continuity mistake: In "Citizen Kang", when Kang and Kodos are transformed into Clinton and Dole, Homer is standing in front of the control panel and you can see in front of him there are several buttons, but in the next shot there is now only a green and red button in front of him.
Continuity mistake: In "Citizen Kang", when Homer is fishing, you can see behind him on his boat there are a brown box and a rolled up mat, which is standing up. But when we see a view of Homer's boat from the UFO, the mat is now lying flat on the back of the boat and the box is now coloured red.