Audio problem: At the end of the movie Chris calls to Father Dyer from her car and says, "I thought you'd like to keep this". If you read her lips she just says, "I thought you'd like this". (02:05:25)
Audio problem: After Chris is startled by the exploding flame in the attic there's a shot of the bell tower of a church as a priests carries flowers into the courtyard. If you look closely the bell we hear overdubbed from the tower is not moving. (00:31:05)
Audio problem: In Doctor Klein's office Regan spits at him as he tries to give her an injection. We hear it but if you look closely nothing comes out of her mouth. (00:47:10)
Answer: It was indeed Pazuzu, he wanted Regan to believe he was some friendly entity to gain her trust. Thus the Captain Howdy facade.