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
Plot hole: At the Amazonian contest, the stadium is full packed with people spectating the event. When Joker attacks their queen and Wonder Woman, they do nothing. No panic, no revolt, no riot, not even a sound. Yet Joker just knocked out their queen, turned the other Amazonian warriors to his side with Joker Gas, and took out Wonder Woman, all in front of them. (00:11:30)
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)