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.
Continuity mistake: Prior to bringing Ray up for the role-playing exercise, the parenting teacher erases a circled phrase from the chalkboard. Throughout the scene, the chalked circle flips several several times between being totally erased and having a faint outline left over.
Dick and the Single Girl - S2-E24
Continuity mistake: When Sonja takes Dick's belt, she has it in her right hand, away from Dick. In the next few shots, Sonja no longer has the belt, but it is back around Dick's pants. Yet the next shot (at the door), it's in Dick's hand. (00:16:30)
Continuity mistake: In the episode when it's Kenan's birthday, Kenan and Kel are looking for Kenan's present in Kenan's parents room. As they're searching, Kel throws some of Kenan's parent's clothes all over the place. But then when Kel throws the snowglobe, there is practically no mess, but just a few clothes on the floor - less than before. Some clothes on the bed disappear as well.
Third Aunt From the Sun - S1-E7
Continuity mistake: As Mr Pool is writing 'Dermus' on the blackboard, the amount of word he writes and the appearance of it changes during shots. (00:02:10)
Star Check Unconventional - S2-E37
Continuity mistake: After the fight between Dexter and the large woman, the old Chinese woman who is sitting down has a collectible Barbie doll to the right of her in a glass case. After Dexter knocks the Barbie doll over and it breaks it cuts back to a shot of the Chinese woman and the doll is still in the case with no damage to the doll or the case.
Continuity mistake: When Steve sings the Blue's Clues theme, he is wearing tan shoes he wore in few other episodes. When he drops his notebook after the theme, he is back in his brown shoes.
Not in the Line of Fire - S3-E15
Continuity mistake: When Mike is watching the tape for the last time, it shows that he was protecting Nicki. We can see a reflection of Mike's office, and the doorway. It's completely empty, but when the shot changes Nicki is standing right there. (00:20:20)
Ruri chan 'Kôkai nisshi' - S1-E5
Continuity mistake: Right after the mid-episode intermission the head cook dismisses the kitchen crew; the leftmost one in the second row has a ponytail swinging to her left, but it's centered in the reverse shot. (00:11:45)