Revealing mistake: When Andi walks into the library (this is not Andi's dream) it cuts to the librarian sitting at her desk and we can see the shot is flipped - note the bookcase and the librarian's buttons. (00:10:40)
Revealing mistake: When Pablo as the ping pong bandit takes Tyrone's paddle, Tyrone asks if he can play Pablo again so can get his paddle back. When Pablo walks into the frame, his skin clips out of his coat. This also happens when he does the "Bandit Slammit".
Continuity mistake: When Katara is trying to heal the wounded earthbender, she gives Sokka the idea to take down The Drill from the inside. Sokka then stops her from saying anything while she is sitting down, and she is wearing her necklace. When she stands up in that same shot, the necklace is gone, like they forgot to animate it. (00:07:35)
Continuity mistake: When Richie gets up from a table at Arnold's to meet with the Fonz in the men's room he's wearing jeans. When he enters the men's room he's wearing grey slacks. (00:07:50)
Visible crew/equipment: After Graig returns Patty's math book, Cathy tries to use the pamphlet's rules as she follows Craig. When Craig thanks Cathy for helping him with Latin, the boom mic repeatedly pops up into view in the bottom right corner of the screen. (00:18:10)
Visit to a Hostile Planet - S3-E2
Continuity mistake: When the guy shoots the Robinson Robot it leaves a big bullet hole on the front. In the next shot we see the Robinson Robot turning around and the bullet hole is gone.
Continuity mistake: In Alex's government class, the professor wrote "Free Speech" on the chalkboard. In a few of the following shots the handwriting differs, and in some shots the phrase is underlined, but in other shots, it is not underlined. (00:05:00)