Episode #3.1 - S3-E1
Continuity mistake: When Goodman makes the last guttural noise with his throat burnt by Catherine's rum, Camille's hand is in inconsistent positions between shots, at the side of her head or under the chin. (00:30:50)
Episode #3.1 - S3-E1
Continuity mistake: When Camille introduces Humphrey and her mother, the extras in the background make various gestures, with in particular the man at the right edge of the frame suddenly drinking off his bottle in the shot when Kris Marshall says "Thank you." (00:29:05)
Episode #3.1 - S3-E1
Continuity mistake: Camille has a moment of grief with her mom, but Humphrey arrives with "Ah, Dwayne said I'd find you here." Catherine turns around and puts her arm on the chair's back before the cut to a new shot, when she is still holding Camille's hand. Similarly, Camille then introduces Goodman leaning back with her arm on the back of the chair...or not, since in the wider angle her arm is down. (00:29:00)
Episode #3.1 - S3-E1
Factual error: In the close-up of the letter accompanying the package sent by DI Richard Poole's parents, their address is from Oadby, Leicester, with a postcode starting by OL9, which is the designation for Oldham, in Lancashire. (00:26:00)
Episode #3.1 - S3-E1
Continuity mistake: When DI Humphrey Goodman says "So, we're left with four friends", Dwayne behind him is holding some documents. Change of view, and he is leaning with both hands on the desk. (00:19:50)
Episode #3.3 - S3-E3
Continuity mistake: When listing the size of Saint Marie, the road is dry. When the shot changes to outside, the road is wet. (00:21:40)
Episode #3.3 - S3-E3
Continuity mistake: When Humphry is reciting the size of Saint Marie, look in the wing mirror to see a trail of vehicle behind the 4x4. When the 4x4 is passing a camera on the side of the road, the trail of vehicles has disappeared. (00:21:40)
Episode #3.5 - S3-E5
Continuity mistake: The land rover is going on a track but the next shot inside shows a road in the side mirror's reflection.
Answer: There's probably no particular reason. Sets and props on long-running TV shows often change as needed and for various reasons throughout a series run.
raywest ★