Mr. Fish (a.k.a. Goodbye, Mr. Fish) - S1-E2
Continuity mistake: While some of the family is eating, the cup in front of Denise disappears than reappears.
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.
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.
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.
Continuity mistake: Rudy takes the coat from one of the kids and puts it on the back of the chair Cliff is sitting on, at one point it falls off, it then reappears behind him, then moves to the table next to him.
For Men Only - S8-E9
Continuity mistake: When Russell is teaching Olivia and her friend how to play "pick up sticks," part way through the sticks at the end of the table close to Olivia disappear.
Continuity mistake: Clair comes into the kitchen and puts some bags on a chair. The next time they are seen they have changed position.
It's Apparent to Everyone - S8-E6
Continuity mistake: When Russell and Olivia leave, a stuffed animal appears on the table by the truck. When Clair comes in the stuffed animal disappears.
Visible crew/equipment: A boom mic is visible as Cliff gets off the couch and says "I know one thing, they are not going to live here."
Continuity mistake: When Jake is describing the accident, he takes some glue tubs from the counter. Partway through the scene they change to glue bottles.
Continuity mistake: When Theo and his parents are talking in the kitchen, there is a box on the table. The cover is on and Theo is standing in front of the table, the next shot he is standing next to the table leaning on a box and the cover is off.
Continuity mistake: When Theo walks into the kitchen, there are two half gallons of chocolate milk on the stove. When he sees the milk and picks it up there is only one. Theo places it on the table, later the second one reappears on the stove, before he leaves Clair gives him the one that is sitting on the stove, and the one on the table disappears.
Continuity mistake: Theo walks into the living room eating a banana and holding an apple - he eats the banana throughout the scene. At one point he starts eating the apple, the banana peel disappears, and a mandarin orange appears on the couch next to him.
Continuity mistake: A root beer comes down the tube and Theo catches it. In the next shot Cliff now has the root beer. Also there are 2 root beers sitting on the table, then suddenly Theo and his friend are holding them.
Denise: The Saga Continues - S6-E1
Continuity mistake: Cliff puts his tool belt on the couch behind Denise - there is a hammer that changes position between shots.
Continuity mistake: When Vanessa and Rudy are at the table, the amount of orange juice in Rudy's cup changes a couple of times.
Rudy Spends the Night - S3-E14
Continuity mistake: Cliff puts a paper bag on the counter facing away from him, when Theo leaves it is suddenly facing the other way.
Continuity mistake: Cliff takes the empty orange juice carton out of the fridge and puts it on the stove. When Theo comes in it is now on the counter next to the stove.