Audio problem: When they are trying to escape Koopa and the little caveman speaks, then Luigi answers him, he has the Princess' voice.
All Americans - November 6, 1962 - S2-E14
Audio problem: During the speech where Al tells Sam to quit (to force Chewie to play), Sam says he can't quit but his mouth doesn't move for a couple seconds after the words start playing.
Ore wa otokoda! Ranma chuugoku ni kaeru? - S1-E18
Audio problem: This episode is basically a clip show; the English dub reused lines of female Ranma without redubbing the first ones, from the first episodes with Brigitta Dau. Therefore female Ranma has noticeably two different voices in the same episode.