Rockets, Communists, and the Dewey Decimal System - S1-E2
Other mistake: As Young Sheldon is a prequel series to Big Bang Theory, this episode is at odds with episode 2-13 of Big Bang Theory, "The Friendship Algorithm," in which Sheldon is unfamiliar with books like "How to Make Friends and Influence People," which he reads in this episode of Young Sheldon, produced nine years later but taking place twenty years earlier.
House Party - S2-E5
Continuity mistake: Kelly said her youngest brother can burp his whole name Kenneth Leonard Kapowski in one burp. However in the previous year, Kelly had an infant brother named Billy. According to this info, unlikely Kenneth would be younger than Billy.
Suggested correction: Kelly can have more than one brother because in the episode where Kelly gets her job at the Max she said "I cook every night for my 11 siblings". So he could be younger or just have a nickname.
The mistake is valid because she says her "youngest" brother, not "younger." In the episode "The Babysitters" (which was meant to air in season 1 and produced before "House Party"), her brother Billy is an infant and says his first words. Kelly has 6 siblings and she never said she cooked for 11 siblings when getting a job at The Max. She says she sets the dinner table for 9 people three times a night.
Ironically, the show only reveals 5 siblings each in their own individual episode. (#6 is unknown). Bennett (mentioned), Nicki (seen), Kyle (voice heard only), Kenneth (mentioned), Billy (seen) are the 5 of 6 siblings revealed.
The Séance - S1-E7
Continuity mistake: After Lucy tells Mr. Merriweather that he's invited to the seance, when it cuts to Lucy unfolding the card table legs, note the couch behind her with one normal seat cushion on the left, but in the next wideshot there's an additional shorter cushion under the normal cushion. The small towel also repositions itself neatly on the couch. (00:11:55)
Visible crew/equipment: In the first scene of the episode, a crew member is visible through an open door beside the staircase.
Continuity mistake: Cory is trying to get a date with Cindy when in the episode before they already became boyfriend and girlfriend.
Suggested correction: This series is not meant to be taken in exact chronological order. Most episodes have no dates or time of the year set. Unless we have reference to a date or time period of the year; we have no way of knowing if the continuity is truly off as this series is meant for the episodes to be taken within a generalized time. Not in any specific chronology except for a few where the time period is specific. Neither this episode or the one before it has reference to a date in time.
Suggested correction: While the other correction is wrong, the real reason this isn't a mistake is because the episodes were aired out of order they were produced, which means it's not a mistake within the context of the show. "Bend It Like Baxter" (production code 315) was filmed before the previous episode, "Double Vision" (production code 318).
It May Look Like a Walnut! - S2-E20
Character mistake: Rob is having a nightmare, part of which involves the disappearance of his thumbs. When he finds Laura at home, the script calls for him to say, "I want you to help me get my thumbs back," but he actually says, "I want you to help me get my thumb backs." His thumbs are also still there but hidden (you can see a portion of them in one frame of the episode).
Confinement - S2-E5
Continuity mistake: Ruby asks Ash where the the Kandarian Dagger is. He says that it was confiscated by the police. In the previous episode, she had and used it, and they have not interacted in the intervening time period.
Visible crew/equipment: When Kim is talking to Joan the security guard, a crew member drinking a cup of coffee can be seen in the dojo.
Continuity mistake: This is a mistake for the introduction from seasons 2-20 (1991-2009). When Homer screams, he turns round. You see this in a wide shot. There are no boxes to the right of the door in the garage. However, two just appear out of thin air when he runs through the garage. (00:01:50)
Other mistake: The opening credits for season 5 show June coming out of the front door with a pitcher of what looks like iced tea, and calling for Ward, Wally and Beaver who are all working outside. But the door opens by itself as she comes out, and then closes by itself behind her. If the entire family is outside, who opened and closed the door?
Shoes, Hats, Pickle Jar Lids - S5-E9
Revealing mistake: When Charlie is in the Ferrari, his gets a call from Teddy. When Charlie brings the iPhone to his ear and talks to Teddy, you can see that the iPhone is upside down showing that no one actually called his phone.
Klink for the Defense - S6-E19
Continuity mistake: General Burkhalter is eating Klink's dinner. When finished he places a metal cover over the plate. In the next shot the cover is lying on the table and there is extra food on the plate. (00:15:25)
The People vs. the Fonz - S11-E11
Factual error: When the Cunninghams are talking about Fonz's trial, Mr. Cunningham can be seen wearing a digital watch. Digital watches didn't exist in the 50's.
Continuity mistake: While Tori is getting her mask removed, another shot shows her sneaking back on stage, but the next shot shows her still getting her mask removed.
Revealing mistake: S9 E1 "Bully for Ben": When Ben hits the punch bag sideways, it's easy to tell that someone is controlling the punch bag as it never slows down.
Continuity mistake: When Kelly is putting the number card on Logan, you can see one on Kendall behind him, when he shouldn't have had one yet.
Factual error: A character in the episode has invented denim, but denim was invented in 1873 and was being used widely up to the time period of the series, which is set in 1893.
Suggested correction: The entire series was set in an alternate history of sorts, so most, if not all, historical "inaccuracies" cannot be regarded as mistakes.
Factual error: In the mall where Jimmy meets Irene there is the Pandora logo in the background when Jimmy is going up the escalator. Pandora didn't open its first store in New Mexico until 2013. (00:27:00 - 00:28:00)
The Spanish Inquisition - S2-E2
Revealing mistake: At the very end when The Spanish Inquisition bursts into the courtroom, you can see that Biggles is not played by Terry Jones (as he is playing the accused judge in the court sketch).