Visible crew/equipment: In the the episode "In-console-able" from series 19, in the kitchen when Paul accidentally puts custard and hundreds of thousands on a dinner, he puts the lid on it and when the camera zooms in you can see a cameraman with a camera recording and Barry getting ready for his take.
Other mistake: In the starting titles, the newspaper clippings state that Doogie sails through high-school in 9 weeks, the article says he is 12 years old. The next clipping says he graduates from Princeton at age 10.
Revealing mistake: Patty Duke's stand-in is visible behind Cathy when the family is in the front hall welcoming their aunt.
Continuity mistake: The package Steve received from Mailbox is briefly visible before Mailbox comes in. You can also see a crew member's hand holding the package as Steve grabs it.
The Fall Guy - S1-E4
Character mistake: Thorny tells Ozzie that Clara Randolph is throwing a party. When Ozzie tells David and Ricky about that party, he calls her "Mary Randolph."
Audio problem: When the tryout team is heading back home led by the Nankatsu trio, their lines (even in the original Japanese version) do not match the mouth movement at all (Misaki's is animated to open randomly, and Tsubasa's moves too frequently). (00:20:40)
Flipper and the Bounty - S2-E13
Visible crew/equipment: After Bud wakes up all alone in Bligh's cabin, he soon realises all the doors are locked. Then, just as Bud rushes over to the stern window (particularly the second time), a seated crew member is visible at the bottom right corner of the screen; we can see the movement of a leg and two hands (so, it's not a mannequin).
Continuity mistake: When Yakko points to India, Africa, except for Egypt and Madagascar, is shown as one country until he points to Tunisia.
Spider's Little Daddy/Tricycle of Terror - S3-E1
Continuity mistake: Mandy's working on her report. The page she's on says "CORN by Mandy." A moment later, she writes the same title on another page.
Triumvirate of Terror! - S3-E8
Continuity mistake: When Joker zaps Wonder Woman and her mother, they are both standing in front of their thrones and fall forwards. But when Wonder Woman stands back up, her mother, still unconscious, is suddenly off to the side and behind the thrones. (00:11:35)
Deliberate mistake: Season 2, episode 6 "Identity Crisis": When Bizarro starts decaying into the parody form of Superman, his costume goes with it; the blue fades, and even the 'S' insignia changes. Strange that superhero garments change right alongside their wearers when they suffer from an unstable genetic effect. Were the clothes cloned right onto his body, instead of sewn?
The Addams Family Goes to School - S1-E1
Continuity mistake: After Mr. Hilliard goes through gate and nears the house, it's really at the real house. A second later, he's approaching the now-familiar front porch on the studio set. This is easy to tell because the layout of the two porches are radically different.
Continuity mistake: After Molly tries the experiment and takes off her safety googles, they reappear and disappear randomly when she hugs Ed.
Emergency Marineville - S1-E11
Continuity mistake: When the second group of Spearhead jets take off from Marineville there are only two jets, but in the next shot you can see three jets, and in the next shot there are two again.
Factual error: Bessie says she was going to study veterinary medicine at Texas A and M. That would have been approximately 1940. Neither women nor people of colour were admitted to TAMU until 1963 so she could not have even been able to apply.
Fruit Picking Day/Daniel Is Big Enough to Help Dad - S1-E11
Continuity mistake: The fruit on Miss Elaina's hat changes colors.
Continuity mistake: Before Charlie says to Lola "You must double-triple promise you'll never play with it", he places the rocket beside a black box. Later in the episode, when Lola attempts to get the rocket down to play with it, the rocket is now on top of the black box.
Continuity mistake: When Dum-Dum cuts the rope releasing Chug-a-Boom from the balloon, we cut to the car and you can see Clyde and Dum-Dum are surrounded by the rest of the Ant Hill Mob, but when we see the two in the next shot, the other members are nowhere to be seen.
Continuity mistake: When Janet gets off the phone with Clarissa's principal, Clarissa is standing on the right side of her friend. The shot changes and she is now on the left.
A Case of Overexposure - S5-E8
Continuity mistake: In season one episode 16, Arnold says that him and Willis never met their landlord. In this episode they remember him as Mr Darcy - when they see him they recognise who he is.