Audio problem: During the Walmart scene, it seems they edited in Gary saying "Oh, God." However, it's over no visible mouth or throat movements. (01:15:17)
Audio problem: When Peter is sitting next to Grandpa in front of the fireplace, he has several consecutive lines when he's seemingly reading off a cue card, and his mouth movements (or lack thereof) do not match the audio. (01:25:00 - 01:25:21)
Audio problem: When Kevin enters the car he says hi to his dad, and as it pans to the other side the dad says hi, but you can see he does not talk and it is not his voice. (00:06:04)