Audio problem: When Samantha and Carrie are in their room on the train, Samantha starts to pour herself a glass of champagne. We hear it pouring for a few seconds until it sounds like the glass is full but when she puts the bottle down, there's barely anything in her glass.
Continuity mistake: When Charlotte is signing her divorce papers, there is a close-up of Harry's face leaning over her. It's covered with large drops of sweat, some of which drip onto the paper. But in the next shot of Harry when he is standing up, he isn't nearly as sweaty. Most of the perspiration on his face seems to have disappeared.