Audio problem: Catherine has been a character on the show from season 1, almost the first episode. Never has she pronounced the name of the island, Saint Marie, like she does in this episode: "Welcome to St. Mary." (00:20:20)
Episode #4.2 - S4-E2
Audio problem: Florence talks about the financial problems of the surfing school. Doing so, she says that they have two mortgages and they "are behind in both." This last part is pronounced with the camera behind Joséphine Jobert, but the timing between audio and jaw movement is off. There's also a little jump in continuity with her left hand away from the sheet/on it. (00:35:10)
Episode #3.1 - S3-E1
Audio problem: Camille invites Humphrey to have a drink with the crew. When he begins to say that "It'd be a bit awkward", Kris Marshall's lips don't match the audio in the brief cut when the camera is slightly behind him. (00:50:25)
Episode #2.8 - S2-E8
Audio problem: Vicky had just introduced herself to Camille when a gunshot is heard. Everyone reacts as you'd expect with such a loud and sudden noise exploded in the middle of a party, everyone except in a brief cut to Duncan Wood. Nobody in that shot is perturbed by the bang in the slightest. (00:02:50)
Episode #1.7 - S1-E7
Audio problem: In a typical movie clichè, the snake at the neck of the ophiophilist member of the band produces the characteristic insidious sound of a rattlesnake despite being a python.
Murder on the Day of the Dead - S7-E5
Audio problem: The address on the satnav is 35 Rue Dauphin, but Ardal O'Hanlon says 35 Rue D'Orphan (the close captions say as much too, it's not a personal interpretation). Florence correctly types Dauphin. (00:35:00)
Murder on the Day of the Dead - S7-E5
Audio problem: When Jack and Florence talk to the club treasurer drinking lemonade, several times in shots where Ardal O'Hanlon is out of focus in the foreground you can hear his voice being dubbed in while he was doing simple a stand-in role without opening his mouth. (00:26:20)
Answer: Most likely they had only tropical exotic drinks, he wanted an old fashioned English beer.