Continuity mistake: In Season 2 Episode 22, Model Behavior, Woody has gotten his braces off. However, in this episode, he has braces back on again.
A Remedy To Cure All Ills - S1-E6
Character mistake: King Uther calls the Lady Morgana, Morgause. (00:11:50)
Triumvirate of Terror! - S3-E8
Continuity mistake: Lex busts through the glass doors in S.T.A.R. Laboratory and the glass falls to the ground. In the wide shot, it is yellow. But in the close up of Lex's feet, the glass is suddenly clear. There is also more of it in the close up. (00:05:35)
Land of Hold/Penny Henny - S2-E17
Deliberate mistake: When Garfield brings Jon to the broken TV, the scene's animation is still unrendered. (00:01:04)