Continuity mistake: In the scene where Bart and Homer find Marge's paintings in the attic, there is a shot of the paintings all stacked up and you can see that the edges of all of them are the same shade of pink as The Front painting. However, when the boys flick through the paintings, the backgrounds and edges are a variety of colours, including pale blue.
Continuity mistake: After Lisa paces around the school hallway practising how to ask Mr. Bergstrom over for dinner, when she opens the classroom door there's a backplate behind the doorknob and a lower panel under the window, but when she sees Miss Hoover and gasps, the backplate and lower panel have both disappeared. (00:13:35)
Continuity mistake: When Lisa opens the classroom door (opposite the teacher's desk) and is shocked to see Miss Hoover has returned, note the door opens outward (into the hallway) and the doorknob is on the right side of the door. When Lisa runs out of the classroom, that door now opens inward and the doorknob is on the left side of the door. (00:13:40)
Continuity mistake: While Homer is in Lisa's bedroom trying to make things right with her, there are three pictures taped to Lisa's mirror. After Homer tells her the music may help, in the next shot Homer walks over to stand behind Lisa. Those pictures taped to Lisa's mirror are weirdly behind Homer's reflection, as if the pictures are taped to the wall behind Homer. Three shots later, when Homer tells Lisa he can fix the dollhouse, his reflection is accurate in relation to those three pictures taped to the mirror. (00:19:20)
Revealing mistake: When Ned says "Crème de cassis" while describing what was in the drink he made. There are several animation errors in this shot. His head is disconnected from his body, and his nose disappears. Also, a part of his face is missing between his fingers while he does the 'OK' hand gesture.