Audio problem: While Chrissie is being attacked at the start of the film, when her mouth is visible it is not in sync with her screams. (00:04:15)
Audio problem: As the shark is towing the Orca, Hooper, Brody and Quint are at the stern cleats with the water splashing up in their faces. Their shouting does not match their mouth movements. Particularly when Hooper shouts, "It's impossible! It's impossible!" he is sticking his tongue way out, making it rather difficult to shout anything at all. (01:44:35)
Audio problem: When Charlie shouts, "Hey! He's takin' it! He's takin' it! He's takin' it!" his lips actually say something else. (00:26:20)
Audio problem: Alex asks his mom if he can still go in the water, and when she says, "Just ten more minutes," although it is a side shot of her face, it is easy to see that her mouth movements are not in sync with her words. (00:13:50)
Audio problem: When the old fisherman yells at his friend to swim faster and not to look back, his mouth movements aren't consistent with what he is saying. (00:25:55)
Answer: Possibly a scar from having his appendix removed, I've been told.
The appendix shot is Brody - he is feeling inferior as the other two share tales of the sea and the only scar he has is from his appendix being removed.