Audio problem: When walking through the Ministry, there is someone selling the Daily Prophet and calling about it. Camera shows a shot from the air and the person can still be heard shouting about the Daily Prophet, but you can see he is talking to someone. (00:18:15)
Audio problem: When Flitwick is leading the choir, just before Umbridge obnoxiously uses the tape measure to note his height, Flitwick says, "Move those mouths," but his mouth is not in sync with the words. (00:47:50)
Audio problem: When Luna and Harry converse, as she posts signs for her 'lost' belongings, in the overhead shot of her dangling sneakers she says, "If not always in the way we expect," but her lips are not moving. (02:01:45)
Answer: When Voldemort originally attacked Harry, he was acting on information provided to him by Snape. But Snape's information was not complete, ergo why Voldemort lost his powers. He wants the prophecy in order to hear it in its entirety, because he believes it will give him the information he needs to kill Harry.
Cubs Fan ★