Revealing mistake: When Frasier comes into the chalet after skiing he doesn't show any of the visible effects after a hard day on the slopes. Meaning, his face isn't even flushed from the cold, his hair is perfectly combed after wearing a hat and there is not even a drop of snow on his boots.
Continuity mistake: When Coach walks out from behind the bar near the start, he's got feathers almost up to his knees. Then when he turns around to walk back, they're now only over his feet. (00:03:55)
Plot hole: At closing time, Cliff, Norm and Woody spontaneously decide to go to Cliff's house. Sam then enters the bar after his date at Melville's. Later in the scene, Rebecca asks Sam about the 'Three Stooges', to which Sam sarcastically replies that they went to Cliff's house. But how could he possibly know that since he entered the scene after they had already left.
Other mistake: Right after Sam tells Carla he will sleep with the next woman who walks through the door, in the background there is an "Extra" (blonde-haired woman seen in the background behind Carla) who starts to cross right then turns and crosses left then turns right and stops and looks confused as to where she is to cross. Obviously she was given directions of which way to cross and when, but forgot. (00:04:15)
Continuity mistake: During the scene when Sam and Diane are left alone in the cockpit, the position of the curtain behind them keeps changing. When Sam is speaking, the curtain is half open. When the camera angle switches to Diane, the curtain is closed.
Continuity mistake: In the scene where Carla is sitting at a table in the bar, dressed as the new Madame LaCarla and is voicing her doubts about being the new Madame, you can see that Carla is only wearing one earring, the left. In other scenes she is wearing both.
Continuity mistake: After dinner Sam pours Sheila a nightcap, and he opens a (seltzer?) bottle for himself. Sheila leaves, and both her semi-filled glass and Sam's bottle are on the counter. Just as Sam opens a second bottle for himself Rebecca enters, and Sam soon sets his second bottle down near his first. In following shots the amount of liquid in Sheila's glass increases, and Sam grabs his first bottle then walks away, but when Rebecca stands up, Sam's first bottle is back on the counter and it's his second bottle that's missing. (00:20:20)
What is... Cliff Clavin? - S8-E14
Continuity mistake: Just before they reveal the answers of Final Jeopardy, they take a wide shot, and Cliff's question (Who are 3 people who have never been in my kitchen) is already revealed. But when they take a tight shot and ask Cliff to reveal his question, it is covered up.
Continuity mistake: After Diane's 'Romance is in the air' Sam comes closer to her and stands right behind her. Then there is a cut and suddenly Sam is standing to her right, shoulder to shoulder - it's a different angle, but the distance is too great. (00:03:30)
Continuity mistake: When Rick Walker is in the bar with Sam, he recognizes Coach as a former pitching coach for the Boston Red Sox. Yet in future episodes of Cheers, Coach is always identified as a former third-base coach.
Breaking in is Hard to Do - S9-E7
Continuity mistake: Rebecca walks to the bar, busily writing her love-letter to Robin on a notepad. As she speaks with Sam, she tilts the notepad toward the camera. We can see it is blank.
Visible crew/equipment: At the end, Sam gives up trying to get the phone number of the woman at the table. As Sam walks back to the bar, Cheers director James Burrows can be seen directing an off-screen camera. He is the bearded man wearing the green shirt.
Continuity mistake: In the scene where Sam talks to Henri, we can see Sam wearing a wedding ring. Of course, in the show, as a great lady's man, Sam is not married. (From 6:39 to 7:57).
Revealing mistake: When Rebecca is in the office and throws a drink on Sam, the pattern of wetness changes on Sams shirt.
Other mistake: After Andy leaves with his girlfriend, Diane goes to call the cops. Problem is that when she lifts the phone onto the bar, there's no cord connecting it to the phone jack.
Character mistake: Cliff tests Norm's memory by asking him who the bad guy in 'Herbie The Love Bug' was (presumably meaning the first movie, which was just 'The Love Bug, ' no Herbie in the title, and not the TV series that actually had the 'Herbie, the Love Bug' title). Norm answers Keenan Wynn, and is told by Cliff that is correct and that his memory is OK. Wynn was the antagonist in the second movie, 'Herbie Rides Again' (reprising his role from the 'Absent-Minded Professor'). The bad guy in 'The Love Bug' was played by David Tomlinson of 'Mary Poppins' fame.
The Ghost and Mrs. Lebec - S8-E23
Continuity mistake: When Carla is talking about seeing Eddie and the restaurant there is someone at the bar who puts their drink down. The shot changes, the drink has disappeared from the bar, and the person puts it down again.
Indoor Fun With Sammy and Robby - S8-E19
Continuity mistake: After Sam and Robin are done playing darts, Sam puts his darts on the pool table. The shot changes and the darts have moved.
Visible crew/equipment: After Frasier and Diane come in with Dr. Ludlow, Frasier asks Diane to give him a hand, they go and talk over by the bar and you can see the end of the set, the wall ends and there is a curtain. (00:04:10)
Rebound (1) - S3-E1
Continuity mistake: When everyone is talking to Sam about his drinking, there is a empty beer mug in front of Norm when he says "Maybe you are drinking more than you should." The shot changes and his mug is now about half full.
Answer: They sometimes acquire episodes from syndicated reruns. The ones with the cut scenes. Sundance channel have some episodes of M.A.S.H. uncut.