Continuity mistake: In the scene where Theo tries to prank Cliff, and Theo grabs the fake gum, he stuffs the "Bag 'o' Gags" under his shirt. You can see throughout the scene that Theo is holding up the bag with his hand. Later on in this scene, the bag drops. In the next shot, there is something green showing from underneath Theo's shirt (The Bag 'o' Gags). Then in the next shot it is hidden again, being held up by Theo's hand. (00:03:55 - 00:05:55)
Other mistake: During the scene where the twin sisters were singing their song, Theo was asked by Cliff to go to Peter's house and ask his mother if he could stay. Theo left immediately after this. But if you look closely while the twins are singing, you'll see Theo's arm in the scene. When the twins finish performing, they sit down. After this, you see Theo coming through the door after having just gone to Peter's house.
Visible crew/equipment: Look closely when Clair gets up after saying to the kids "I'm glad we had this chat", you can see a tip of a camera on the right.
Audio problem: When Rudy and her friends make a recording of spooky noises, then play it back while trying to scare Cliff, the noises on the tape go on much longer than when the kids recorded it.
Mrs. Huxtable Goes to Kindergarten - S5-E14
Continuity mistake: In the previous episode they got a new couch, in this episode the old one is back.
Revealing mistake: Rudy snatches a hat off Kenny's head and she says the line: "Gimme back my hat Bud!" At same time, you can see the actor who plays Kenny silently mouthing the line with her. (00:12:50)
Theo and the Kids (2) - S7-E26
Other mistake: After the commercial, when Olivia and her friend are watching TV, they look at each other and laugh, obviously on cue. They weren't even looking at the TV and started laughing at exactly the same time.
Some Gifts Aren't Deductible - S8-E23
Revealing mistake: When Stanley comes into the kitchen he has three demands, on paper from Deirdre, to which Kenny must agree. After Stanley reads the demands, Kenny signs it. You can plainly see that the paper is blank the moment after he signs it and gives it back to Stanley.
Pam Applies to College - S8-E4
Visible crew/equipment: If you look carefully, at the very top of the screen, during the scene where Olivia is telling the Huxtables that she didn't get to do her show-and-tell at school, you can see the microphone appear very briefly.
Continuity mistake: At the end of the episode, Theo and Cliff are drinking a soda. Cliff pours half of his in a glass and begins drinking it. When the camera pans for the end of the episode, the bottle that cliff set down is once again full.
You Can't Stop the Music - S8-E22
Revealing mistake: Glue can be seen on Kenny's forehead after the carrot has been removed.
Breaking With Tradition - S1-E6
Continuity mistake: Theo and Cliff walk into the kitchen and Cliff sets the basketball on the counter. Theo walks upstairs. When the camera is back on the counter the basketball is gone.
Continuity mistake: When Vanessa walks down the steps and drops all her papers, they are shown on the steps, then off the steps and then on again.
Continuity mistake: After Theo gives up an extra $100 for clothes, he is holding $300 left in his hand. However when the camera switches back to Cliff, who asks how much is left, it switches back to Theo, who is only holding $200 left.
Cyranoise de Bergington - S5-E8
Other mistake: During the opening scene, Cliff is in his home office, located in the basement of his home. The phone rings. He walks over to his office desk, then presses the speaker button. An unfamiliar female voice is heard speaking, as she states that someone is there is see Cliff. Who is that woman? Where is her office desk stationed? She is never heard, or seen, ever again within this episode, and throughout other episodes, prior or after. This is S5E7. This website has the season and episodes mismatched. (01:19:00 - 01:39:00)
Suggested correction: It sounded like Clair to me. And in regards to who that someone was, it was Rudy. So it wasn't as if it was Dr. Huxtable's secretary announcing a patient, or a secretary who didn't know who Cliff's kids were. It's easy to picture Clair acting like a secretary for her daughter's sake so that Rudy could come in and talk to her dad while he's a work, without Rudy just running in and disrupting him. Plus, his phone didn't ring, it was the intercom that Clair would have used from another phone in the house.
Clair is not seen speaking into a speaker, at any time, during any episode, throughout the entire show's existence, and that woman's voice does not sound like Clair's. In addition, Cliff exchanged with 'the mystery female' in a professional manner/tone of voice, like a boss would to an employee, an not in his usually playful, loving voice, that he normally speaks to Clair with.
Continuity mistake: Cliff and Clair are talking in the living room while Cliff is making a sandwich. As Clair asks Cliff if he would trust her with a sexy man, Cliff starts putting potato chips on his sandwich from a bowl. As he takes the chips out of the bowl, the level of chips goes down. When Cliff asks Clair if she would trust him with a nineteen year old woman, the bowl is miraculously at the level it was at the beginning of the scene. But as Cliff finishes talking, the bowl is back to it previous level.
Factual error: When Clair and Denise are watching the Bears vs. the Giants game, they comment on how cute player number 16 is. In 1985, nobody wore 16 for either the Bears or the Giants. Former Bears' placekicker Bob Thomas wore it from 1975 to 1984 until he retired. 16 wasn't worn again by the Bears until Tim Lashar, another kicker, wore it in 1987. Also, 16 had long since been retired by the Giants. It was last worn by Frank Gifford.
Audio problem: After Jade enters the coffee shop she says "Dennis, Darling!" and immediately afterwards you can hear a crew member/the director saying "Cut." Then the scene continues from a different camera/angle. (00:07:20)
You Can Go Home Again - S7-E10
Other mistake: When Denise hangs up the phone after inquiring about the two bedroom apartment, actress Lisa Bonet's multiple tattoos are visible on the back of her neck and shoulder. In every other scene her tattoos are obscured with makeup as they wouldn't fit with Denise.
Continuity mistake: At the beginning of the episode Cliff starts to cut up the sleepover treat, a couple of shots later Olivia's friend says "I knew we should have done this upstairs" - it is now uncut and Cliff starts cutting it again.
