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)
Chosen answer: When Sozin says "So I wiped out the Air Temples," we are indeed seeing the three mountains of the Eastern Air Temple burning, with the two bridges being gone in this shot (S3-E6). This does conflict a bit with the image we see of the Eastern Air Temple, with the two bridges intact, when Aang and Appa fly to that Air Temple seeking Guru Pathik (S2-E19). This may possibly be considered a mistake, but the fact is that when we are seeing the burning of the Eastern Air Temple it's from the point of view of Zuko, who is merely reading from Sozin's autobiographical account, and envisioning everything he's reading, which in his mind includes the bridges having been destroyed.
Super Grover ★