Audio problem: At the end of this episode, Aang tells Katara that forgiveness is the first step you need to begin healing. But if you watch closely, his mouth isn't moving at all when he says this.
The Krakken - S1-E3
Audio problem: When the kraken roars, when it destroys a ship, it sounds like a TIE fighter in Star Wars.
Failure Is Not a Factory-installed Option - S2-E3
Audio problem: Stan looks out the window whilst being suspended from work. As he looks he sees two people exiting their homes and they both say "Bye buddy" and "See ya pal." Their mouths don't move.