Character mistake: When Chessy confronts "Annie" when she's presenting her with the big breakfast, she's talking about when Annie was on the phone the night before. Then she says her father overslept, when she actually meant to say and "and you overslept," as the conversation doesn't make any sense saying that the father overslept. (00:58:00)
Character mistake: Just before Annie and Hallie find out they are sisters in the isolation cabin, Hallie says "Oh hey, it stopped raining!" But you can see outside that it is still raining at a significant rate.
Suggested correction: That's just water dripping off the roof. It was raining before she said that, but obviously quit raining, and then she said, "Oh hey. It stopped raining." It was not raining when she said that.
Character mistake: Annie talks to herself about not being able to handle the situation with her dad and Meredith, before Chessie appears from a chair. Since Annie thought she was alone, it doesn't make sense that she was talking to herself in her fake American voice, before Chessie surprised her.