Other mistake: The outside shots show that the house is in the middle of a row of houses, connected to other houses on both sides. But in the living room, behind the stairs, is a window looking outside. There couldn't possibly be a window there as that is where the house shares a wall with the house next door.
Other mistake: It is daylight outside when Cliff and Clair are talking, but when he turns the lights off to try on his light-up Father's Day gifts, it gets pitch black in the room.
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.
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.
Other mistake: When Denise and Rebecca are in the kitchen, Denise is playing a tape recording of the rap session from Uncle Wilton when they were doing the math rap. However, when Denise was attending the class, she never had a tape recorder, so there is no way she could have recorded anything.
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.
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.
