Episode #1.1 - S1-E1
Continuity mistake: Sgt. Lily Thomson drives detective inspector Poole to the beach shack. In the opening wide shot she has her left hand on the steering wheel, but in the closer angles the hand at 12 o'clock is the right hand instead. (00:09:10)
DI Humphrey Goodman: If I am gonna woo the ladies with my culinary skills, I think I need to invest in a cookery book.
DS Florence Cassell: I don't know. Maybe turning on the oven would be a good start.
DI Humphrey Goodman: Yes. The devil is in the detail. (00:24:50)
Trivia: A bit of the episode has been cut for the streaming releases; at the end of the scene with Humphrey taking Martha's luggage, he would make a date with her for the next day, to cook dinner for her at 8. This has been eliminated probably because it created timing issues with 8 PM being too well lit (in contrast with the supposed timing of the murder) and the ending takes place at Catherine's for a cute drinking scene anyway. (00:22:50)
Question: Why did the cord on the wall phone in the police station change from straight in the early episodes to coiled later?
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 ★
As long as such changes aren't an obvious continuity mistake (e.g. changing multiple times during a day), one can just assume the change happened in-universe as well. Things do get broken or updated occasionally. It adds a bit of realism, in my opinion.