Factual error: When Roy is electrocuted and falls from the roof, after Karen uses the defibrillator paddles on Roy, she lifts both paddles, looks at the EKG monitor and says "He's converted." How exactly could Karen have known that he's converted? It's impossible for the EKG monitor to show anything at all. Either the defib paddles have to be in contact with Roy's body for the "quick-look" to get a reading, which they weren't, or the ECG electrode discs have to be on Roy's chest connecting him to the EKG monitor, and they weren't. As an aside, just watching Marco having problems attaching the air mask, and quickly glancing up towards the camera frustrated, then giving up is priceless.
Goodbye, Farewell, and Amen - S11-E16
Other mistake: How did Hawkeye Pierce, a surgeon, know how to drive a tank? It is nothing like driving a car and takes skills, training and experience that a surgeon simply would not have. He wouldn't even be able to start the engine.
Continuity mistake: When Fred takes his plate from one room to the next, they switch from a small object on the plate in the living room to a full size Danish when he walks into the kitchen screen.
Visible crew/equipment: At the mill, when John tells Buck that Willie Brimmer might be at the Montgomery cabin with Jim-Bob, in the next closeup of John we see a billowy trail of cigarette smoke at the bottom right corner of the screen, but the only people standing there are Elizabeth, John, and Buck, and none are smoking. Presumably, it was someone offscreen smoking too close to the camera (similar to a mistake in 1978's "Halloween"). (00:26:05)
Not with My Sister You Don't - S1-E19
Character mistake: Howard Borden goes to Bob's office and says it's the first time he's been there. In fact, he had come to the office to address Bob's "fear of flying" group in the first episode.
German Week - S3-E6
Revealing mistake: When Mr. Humphries and Mr. Lucas make their toast with the German mugs, Mr. Lucas' mug breaks but Mr. Humphries' does not. A moment later, when Mr. Humphries notices the mug has not broken, you can see that he crushes the mug with his hand.
Continuity mistake: Just after Otis makes the ghost sounds from inside the house, it shows the gang standing together outside the house. Otis is with them outside, which is impossible, as he is inside the house pretending to be the ghost.
With This Ring, I Thee Kill! - S1-E7
Factual error: Rhodes views the silent movie and the film breaks, leaving the last frame frozen on the screen. Wouldn't happen. When 16mm film broke in 1970s projectors, any portion that jammed in the mechanism was exposed to intense heat from the projection lamp, and would burn. (00:35:30)
Visible crew/equipment: As the old Indian sets fire to burn his dead son, he walks towards Cain and on the left you see a fire extinguisher. (00:10:04)
Continuity mistake: As Banacek approaches the room in the farmhouse that has the cross, he has a cigar in his mouth. As he enters, the cigar is gone.
El traje del tío Jacinto - S2-E16
Visible crew/equipment: In the credits, there's a unknown person hiding behind Don Ramón (Raymond).
Continuity mistake: Towards the end of the episode, Maude makes Walter breakfast and lists some things she will get done around the house. One is to paint the kitchen chairs. She spray paints the chair with Walter in it - the amount of spray paint on Walter's jacket changes thoughout the scene, especially when Maude is on the phone turning down a job.
Blödeln auf die feine englische Art - S1-E2
Other mistake: In the "Happy Valley" segment, when the witch is just about to enter the cathedral, you can see a car drive past through the windows behind the altar. (Now, this is Monty Python, so we have to be careful... But is isn't clear, or funny, enough to be there on purpose).
Visible crew/equipment: Episode 1713: When Kathy says, "I can't quite believe I'm hearing this, " when she and Kim are talking in the lounge, the boom mic is visible at the top of the screen.
Continuity mistake: When Batman and Robin guest star on the show, Batman's cowl changes from covering his neck to exposing his neck.