Other mistake: The Air People were wiped out by the Fire Nation through Suzon's Comet enhancing them, we even have confirmation of this by the dishevelled exposed skeleton of a VIP of them (presumably any Air Nomad who escaped would have given Monk Giatsu honorable burial), but we never see scorch marks on the Air Nomad buildings or the aforementioned skeleton.
The Southern Air Temple - S1-E3
Other mistake: When the gang is in the Hall of Statues of Past Avatars, Katara points out the avatar cycle pattern of statues and Aang zeroes in on Roku's statue. The earthbender avatar statue next to Roku is of an unknown man with a sword, not Kiyoshi. (00:12:50 - 00:13:35)
Bato of the Water Tribe - S1-E15
Other mistake: When Katara is behind Sokka and he is speaking she leans back and as she does her eyes stay in the same place while her head moves, then it fixes itself. (00:16:20)
The Tales of Ba Sing Se - S2-E15
Other mistake: The Tale of Aang: After Aang lets all the animals out of the zoo, he takes out his bison whistle and blows on it. As he does so, the way he holds his staff makes it so that it's going right through his head. (00:10:28)
Other mistake: When Aang is reading the letter from The Guru, as Sokka says, "What's a guru? Some kind of poisonous blowfish?" his right eye loses its white colour three times during the shot. (00:18:19)
Other mistake: When the group is first shown inside the store, Sokka starts running forward. Toph stands behind Sokka, but as Sokka is running away from them, she is layered over him. (00:04:43)
Other mistake: When Azula attacks The Western Air Temple, there is a close up shot of her when she says that she is about to become an only child. Pay attention to the smoke coming from the airship behind her, especially above her head: it doesn't move. Even if this was remotely possible, it does move when the camera zooms out, making it a mistake nonetheless.
The Ember Island Players - S3-E17
Other mistake: When they are watching the recap play Toph says she can't see it because they are on a balcony, but when her character comes on she describes him as buff.
Suggested correction: She didn't see him (or technically, feel him), but she heard him. The actor playing her character throws the huge prop rock, and it hits the stage floor. Then, he flexes his muscles. Toph heard all this happening from her seat and then said, "I sound like a guy. A really buff guy."
