Charlie Goes America All Over Everybody's Ass - S2-E9
Audio problem: When the Vietnamese man is playing Russian Roulette in the end, a few seconds after picking up the gun, he moves his thumb and we hear the gun cock. However, you can see that he didn't actually cock the gun, as his thumb never came into contact with the hammer while moving, hence the sound was a phantom sound.
The Gang Makes Lethal Weapon 7 - S15-E2
Audio problem: When Dennis is talking about the dates he has been on whilst in the bathroom, after the third date is shown, he says, "This generation doesn't even understand half the shit that they're saying." Whilst saying the line, the camera cuts to focus on the others, and Dennis' mouth can be seen in the corner of the frame, but the movements of his mouth don't appear to match the audio. (00:17:40)