Character mistake: Humphrey tells the riddle of the two barbers wrong; you have to set it up saying that the 'good' barber has a great haircut, not that he's great at cutting hair, or you negate its point (which is that the 'bad' barber with the bad haircut is the one who did the haircut to the good-looking barber, and vice-versa).
Continuity mistake: Humphrey, triumphant for the discover made through his gossip with the roomie of the suspect, slams the yachting magazine on the desk with a swift motion of his right arm, which is the left arm in the next shot. (00:37:25)
Continuity mistake: Early morning at the station. Florence just arrived, and Humphrey is telling her about his suspicions on Nicky Hoskins. She replies that she needed the job; between shots there's an obvious difference in the positions she listens in. She is palm to back at first, then both palms upturned. (00:36:50)
Factual error: The website of the toy manufacturer has as address for its store a location in Harrogate, but the ZIP code has an incorrect format, with the 4th character being an O and not a zero, and HG4 being the neighbouring Ripon. (00:28:30)
Other mistake: It's played as a gag, but still it's quite inconceivable that in "fifteen minutes" it would get pitch dark so that Dwayne can avoid his duties sanding the ship! How much time could he have bought even if he had more excuses up his sleeve? Goodman really can't tell the difference between 15 minutes and a couple of hours? The scene started when it was nowhere near dawn. (00:21:10)
Continuity mistake: On the derelict boat, Humphrey invites Dwayne to do some sanding together, but Dwayne has a counterproposal. Humphrey listens to it with his hand on his hip, away, on the hip again. (00:21:15)
Continuity mistake: Dwayne points his finger at JP telling him his former superior said "a policeman can't have any weaknesses." Reverse shot, and Dwayne's hand is nowhere in sight, but it is a moment later. (00:16:30)
Character mistake: The rap sheet of Laura Hagen's dad says that he served "half of an 12 years sentence." An twelve? (00:15:50)
Continuity mistake: Dwayne mentions enlisting the help of the Saint Marie diving school. At the following cut, his shirt is more open, revealing more of his trademark tank, and he is holding the notepad where it would have been visible in the close-up. (00:09:55)
Continuity mistake: Humphrey and Florence go back on the boat after the preliminary interview. Florence is on the phone with the Coast guard when she gets on the boat; the phone is on her left hand, and the right hand is occupied by the notepad. When she tells Humphrey the coast guard's report, they have traded places. (00:09:20)
Continuity mistake: Laura Hagen is back in the cabin to retrieve the sample bag she forgot. The bag was under a map on the table, which she moves by a whole lot...or just a tiny bit, when the table is shown from another angle. (00:02:25)
Episode #4.8 - S4-E8
Plot hole: The way the murder happened (where was the gun shot from?) is entirely unknown for the first couple of days, not even a hint - it seems the investigators don't care at all about it, which is quite silly per se. More importantly though, knowing so little about the way the shooting happened would have at the very least prompted an analysis of the shirt to check the entry wound and any residual. During that sort of test the 'other substance' used in the trick would have been easily discovered (visually it is radically different up close and drying out), exposing the culprit.
Episode #4.8 - S4-E8
Continuity mistake: When Humphrey is done with the murderer, he walks back to the stand, with Florence fawning over his performance. In the longshot Commissioner Selwyn Patterson 's arm is in the shadow, in the closer angle the shadow goes to half his pec too. (00:47:30)
Episode #4.8 - S4-E8
Continuity mistake: Dinner with the father, part 2. Humphrey is having trouble speaking, and his dad asks "Are you like this at work?" During that shot you can partially see that Mr. Martin Goodman QC is holding the glass of wine, while he's holding a fork in the previous and following. (00:29:25)
Episode #4.8 - S4-E8
Continuity mistake: After the chat with the Commissioner, Humphrey gets infodumped on by his team. Dwayne passes him the insurance documents, then JP speaks about the personal effects of the deceased, just as Goodman split the papers given by Dwayne one per hand. Reverse shot and they are back one stacked on top of the other. Back to the previous angle, and they are divided again. And so on. (00:25:10)
Episode #4.8 - S4-E8
Continuity mistake: Inside Erol Dumas' kitchen, Florence holds the envelope with the money putting her fingers on the empty glove. During a quick cut on Humph though she suddenly wears the glove for the ending of the scene. (00:19:05)
Episode #4.8 - S4-E8
Continuity mistake: Goodman and Cassell are doing the whiteboard routine; when Humphrey asks about the 'refreshments', his marker is uncapped, while it has the lid in the shot before and after. (00:13:05)
Episode #4.8 - S4-E8
Continuity mistake: Everyone is in the cell examining the corpse. The prison guard nods when Dwayne says that they did a complete sweep of the courthouse; his arms are folded. Next shot, his arms are down his sides, and only a second later he folds them. (00:04:55)
Episode #4.8 - S4-E8
Continuity mistake: Humphrey knocks over the flower pot. Florence reacts in one shot from behind raising her arm, but the arm is down again in the instant reverse. (00:00:50)
Episode #4.7 - S4-E7
Character mistake: Humphrey quotes by memory the precedent of adermatoglyphia remembering correctly the name of the patient. He says that it happened in 2008, though, while the date it was reported was 2007.
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 ★