Audio problem: When Jake gets to school, a kid tells him his Good Guy doll is "cool." Jake asks if he wants to buy it, and the kid replies, "No thanks." But his mouth isn't moving. (The shot cuts while he's saying it, but you can tell his mouth isn't moving.)
Audio problem: After Kate shoots an arrow at the mafia guys, she says "told ya." Then we hear Clint/Hawkeye say "yeah", except he's on camera and his mouth doesn't move, he doesn't even change his facial expression.