There's Something About Marrying - S16-E10
Audio problem: Homer is strangling Bart and tells Lisa to hold his spot. You can hear Lisa say, "Why you little," and you can hear Bart choking, but neither of their mouths is moving.
Don't Fear The Roofer - S16-E16
Audio problem: When Marge says "You're drooling on my goodwill pile", her mouth doesn't match her voice.
Audio problem: When Homer says "Burn the truth" after burning his pants, his mouth doesn't match what he is saying.