Twenty Years Ago Today - S4-E8
Continuity mistake: In the scene where Brandon is going back to Dylan's house to retrieve his parents' wedding anniversary gift, when he is in the car and when he jumps out hurrying to the house he has his sunglasses on, but in the next shot with a different camera angle, as Brandon continues to hurry to the house, he has no sunglasses on. (00:22:00)
Continuity mistake: During the scene where David, Donna, and Andrea are in the casino and Andrea puts one dollar in a slot machine and hits the $500 jackpot, she screams and David tells Donna to get some buckets so that they may put all the coins in them. At that exact moment, they are interrupted by a security guard who asks them for their id's and when he figures out they aren't 21, he asks them to hand over the buckets of coins. At this moment, David and Donna hand over at least one bucket of coins. However, between the time David told Donna to get the buckets and when the security guard questioned them, the gang did not (and had no time to) get to fill up any of the buckets full of coins.
Crunch Time - S4-E16
Continuity mistake: At the end of the episode, Steve and John Sears are behind the table and one of them is about to be voted out of the fraternity. Pay attention to the scene where fraternity president Mike Ryan is giving instructions to the other fraternity brothers on how to vote and behave during this process. At the exact scene where Mike Ryan says, 'Your absolute silence is required', in the background we see Steve and John Sears staring down each other in anger. A split second later just as Mike Ryan finishes that sentence, the camera shot now just shows Steve sitting straight forward, looking down at his lap slightly in a kind of sad, defeated state.
Vital Signs - S4-E30
Continuity mistake: Near the beginning of this episode Andrea is awakened at 3 A.M. by an alarm clock to take a pill to stop her preterm labor. Several times in the episode it is mentioned she must take the pill every 4 hours. Later the alarm goes off at 8 PM the same day and she says "time for the pill again that is not doing me any good". If the alarm went off at 3, 8pm doesn't fit the 4 hour timeframe.
Mr. Walsh Goes to Washington (2) - S4-E32
Audio problem: During the scene where David and Babyface are talking and Babyface asks David to fill in as one of the keyboardists for his carnival show, the camera shots going back and forth from both behind David and Babyface show them speaking, but it is very clear their words don't match their lip movements.
Radar Love - S4-E12
Audio problem: During the scene where Dylan and Kelly excuse themselves from the Walsh Thanksgiving dinner to go argue in the frontroom, pay attention to the camera shot behind Dylan when he is telling Kelly that he "just happens to like Cindy's Thanksgiving turkey better than your mom's." His lips do not match what he is saying.
Somewhere in the World It's Christmas - S4-E15
Revealing mistake: At the end of the episode in the Peach Pit, Nat and the gang are all singing Christmas songs while Nat is playing some of the songs on a keyboard. It is very easy to tell by looking at his hands, Nat is simply miming on the keyboard.
The Time Has Come Today - S4-E25
Factual error: The diary that Brenda finds has a Precious Moments figure on the cover. Wendy, the character who owned it, wrote it between January 1968 (an entry mentions her new year's resolution) and August 1969 (when she attended Woodstock), but the company didn't exist under that name until the late 1980s.
Emily (a.k.a. The Pink Pearl) - S4-E13
Audio problem: During the scene where John Sears and some of the keg brothers are telling Steve that one of his hazing duties is to steal Professor Randall's signed baseball, pay attention to the camera shot behind John Sears when he is talking to Steve - his lips do not match what he is saying.
Other mistake: Throughout the entire 4th series and even various times into the 5th series, pay attention to the shots that show the outside of Steve's Kappa Epsilon Gamma frat house. Every single time, you will notice the same exact two people outside of the frat house - one is a guy wearing a green and white striped shirt sitting in the lawn reading a book, and the other guy is wearing a brown or orange shirt lying on the couch outside. While not impossible, these same exact two characters wearing the same exact clothes doing the same exact things outside of the frat house every single time for upwards of a year or more in 'show time' is unlikely.
Continuity mistake: During the scene in the kitchen where Brenda is at the table and her parents are talking to her about Stuart and then ask her if she wants a piece of pie, her arms are out in front of her on the table at this point. A split second later (same sentence), a rear camera view now has her left arm up holding her chin. A split second later after that when she answers "no", the front camera view now has her arms on the table as they had been all long.
Somewhere in the World It's Christmas - S4-E15
Revealing mistake: Pay close attention to some of the scenes on the airplane during the flight that the Walshes are taking to Hawaii. Several times you will see a large, winding (and ascending) staircase in the background of the plane. If you also look close, you will see an 'exit' sign' slightly behind and to the left of the staircase. While some luxury airbuses do have staircases, given the fact you can see an exit sign it is easy to tell these scenes were shot in some kind of setting other than an airplane.
