Audio problem: When we see Mike during the slumber party, we hear seven bells ring for the seven filled cylinders, but there are only six cylinder-filling noises. (00:16:50)
Audio problem: When Marlin and Dory swim into the deepest part of the ocean to reclaim their mask, they see a light (which we know later, belongs to an angler fish). They stop right underneath the light and says "What is it?" but his mouth doesn't match the movements. It looks as though the animators had Albert Brooks (Marlin's voice actor) say a different line than what was animated.