Girl Trouble / School Dance - S3-E18
Continuity mistake: Besides the fact that when Helga is sharpening her pencil, the desk arrangement changes, one of the students visible when she looks at Arnold is... Helga. This happens because the shot is taken from the episode "Helga's Love Potion."
Continuity mistake: Right at the beginning of this episode Kevin and the twins are making sandwiches. Lucy comes into the kitchen and kisses Kevin, then David asks where their (his and Sam's) kisses are. As this scene goes on, the shots ranging from views of all four to focal shots, David's sandwich is finished and on the (viewer's) left side of his plate, then unfinished, topped with lettuce instead of bread and on the right side of the plate. It goes back and forth between these two sandwiches. Also, at about 00:05:04 as Kevin and Lucy walk away, Sam's sandwich suddenly loses its top piece of bread. (00:04:40)
Continuity mistake: In Episode 5, "Live Hard, Die Young and Leave A Good Looking Corpse": As Lillie is preparing to cut Zane's throat with her fingernail, she stands with her hand raised above her head for a while. When seen from the front, her hand is balled into a fist with the index finger extended, but when seen from the back all her fingers are extended. The view alternates like this several times, and each time the hand varies between fist and outstretched fingers.
Home Groan - S3-E21
Continuity mistake: In episode 3-10, Gary's mother Lois is the victim of fraud. He mistakes his mother as a shooter of the conman. The headline specifically states the shooter is an Illinois woman. However in this episode convicts escape to Gary's hometown of Hickory, Indiana. The episode depicts his parents residing there, as though they have always been there.
Episode #2.1 - S2-E1
Continuity mistake: Near the end of the episode, when Simon is showing the photographs to Lloyd, Dinah and Harvey, the photographs on the table move around from shot to shot. (00:21:29)