Audio problem: When Luke says, "Now all we gotta do is find this Yoda, if he even exists," if you look closely, his mouth never moves.
Audio problem: In the scene at the Palace Hotel Ballroom, when the Blues Brothers are singing their 2nd tune (Sweet Home Chicago), you can hear both Jake and Elwood on the soundtrack but Elwood is dancing down the middle aisle without even a microphone in his hand and his mouth is not moving. There is also a shot during the same song where Jake's singing and pauses do not line up with what we see visually. When he sings "baby don'cha you want to go-oh - -" we see his mouth stop moving, then when he pauses, his mouth is still singing. As a matter of fact, the entire number has mistakes like this and mistakes of continuity. (01:54:20)
Audio problem: Before the trio crashed into the Daily Planet (just before the battle with Supes), they were heard flying outside the building. For 3 superbeings with the ability to fly unaided, they sure sound heckuva lot like jet-propelled aircrafts. Jet aircrafts are noisy because of their engines, but superpeople?
Audio problem: Terrible Tommy and Rose exchange words just as their match begins but neither one's mouth opens.