Audio problem: When Ritchie tells Sam, "I'm coming with you," right before they leave the bowling alley, Ritchie's line seems strangely dubbed in. It just doesn't quite match his lip movements for the first half.
Audio problem: When the country music singer tells Parker that Elvis can sing his songs "but no wiggle" there's a side shot of his face and his mouth doesn't match what he's saying.
Audio problem: Blanc and Lionel are talking about Andi on the ship headed to the island. "In one legal move, he cut her out completely", Lionel says, but the second half of the phrase his chin (as you can tell by his conspicuous beard) is not moving. (00:18:45)
Audio problem: There was no sound during the time the scientist was giving his several-word response to, "Do you want a coffee?" (00:16:25)
Audio problem: Katherine visits Poirot at the field hospital; the opening line has a loud gulping, most likely dubbed, and then Branagh's voice says "I asked you...not to come" with the second part of the sentence added in dub; his lips don't move. (00:05:45)
Audio problem: In the original version, it's crystal clear that the last sentence from inspector Gemma Bajani after she hands her calling card (when she says that they'll be back with a search warrant) was added in post, lacking ambience and even mixed at a different level than the rest of the dialogue. (00:39:10)
Audio problem: The baddie enters the room with the two ladies and fires a shot in the air. He is holding a revolver but the empty casing can be heard hitting the floor as if the pistol was magazine fed. (00:39:00)
Audio problem: When Trevor is explaining to Riley how he wants to rob the storage unit, at one point there's an over-the-shoulder shot where he says "Totally anonymous... nobody's ever seen any one in there... but, like the shit..." If you look closely, you can tell Trevor is saying something completely different. True, his mouth isn't on-screen the whole time, but his jaw movements and his mouth movements don't match the words at all when they are visible, revealing they altered the dialogue in post.
Audio problem: In a flashback scene after Anthony says, " It is normal to be a little nervous" and Malia asks, "Is it?", Malia's mouth does not move when she finishes her question, "more rational to be paranoid or careless?" (00:47:13)
Audio problem: Near the beginning of the film, when the sheriffs are chasing Kya, she takes her boat through some trees. The main sheriff says "in there," or something similar. His mouth doesn't match what he is saying.
Audio problem: When the boy and the leader of Iceland are hammering in posts and the boy is complaining that he's the heir and shouldn't have to do manual labor, there are at least two times when bad wind flutter in the microphones can be heard. It sounds like the wind clips the volume level and the audio briefly cuts out. It happens on windy film shoots, as wind screens can only prevent so much and its obviously very windy in this scene. Why this wasn't caught in post is hard to say. This is audible on the video on demand version.
Suggested correction: No such problem exists on the UHD/Blu-ray release. I also did not notice it on the VOD release, so it could have just been an issue with your sound setup.