Audio problem: While Bing Crosby sings "White Christmas," he is playing the piano. However, the piano is never heard.
Audio problem: There is a clear lip-sync problem in the boat scene, after Eugene takes out the lanterns.
Audio problem: In the last scene when Vlad, Michael and Ellen are swimming, Michael is talking as he enters the water. His head dips under water, but you can still hear his words.
Audio problem: When we see the moth singing on his way to the bar, his mouth doesn't move.
Audio problem: When Warren T. Rat calls open season on Fievel, the cats all scramble at once to capture him. In one shot where Fievel is running from either end of the piano, he jumps upon the same key twice. The notes play, but the key never goes down at all. (00:51:55)
Audio problem: At the illegal fight, as Castor and Oxheart get ready to fight, Oxheart's mom says "Don't kill him. Just rough him up a bit." you hear the lines, but her mouth isn't moving.
Audio problem: When the wolves attack Maurice and Philippe, the wolves make growls that only big cats (lions/tigers) would make.
Audio problem: After Chico and Harpo first meet there's a man at the opera playing a drum. Not only is he out of sync with the sound we hear, but he is mimicking the blows.
Audio problem: During "This is me", when they enter the room and get to the "oooh oh oh" part if you watch the albino the sync is out as their mouths open after the music has ended on that part.
Audio problem: While Thomas O'Malley is saying "all right now, don't panic" his mouth is not moving.