Other mistake: When Cat picks up the can of Leopard lager which is invisible to Lister, he shakes it, pops the cap and sprays Lister with foam. The foam is visible but the can remains invisible, and that makes no sense. If we are seeing the scene from Cat's point of view the can and foam should both be visible, and if it is from Lister's then neither should be.
Other mistake: In the first episode it shows the house a mess and Danny and Joey and Jesse not wanting to clean. Then in the future the show portrays Danny as always being a neat freak, even as a child.
Other mistake: In an earlier episode where Edie and Susan are driving Martha Huber's ashes to the lake to be spread, Edie gets a flat tire and Susan changes it. In this episode, all the girls are driving with Edie's ashes and they get a flat tire. Susan asks "Does anyone know how to change a flat tire?" Did she forget how?
Other mistake: When Rachel arrives at Central Perk, Monica introduces her to everybody, including to Chandler, as if they don't know each other. In later episodes, we learn that Chandler met Monica and Rachel a couple of times when they were in high school (including when Monica cut his toe off). Chandler even kissed Rachel once, and since Chandler always says that he hasn't kissed many women, he should have perfectly remembered Rachel, and Monica should have remembered that the two of them knew each other. (00:04:40)
Other mistake: Episodes 4 and 5 of season 1 aired noticeably out of order. In episode 4, "The Nanny," Alex's former Nanny, Rosalba, comes to work at his podcast company, and its name, "Ajana," is mentioned a few times. But episode 5, "The Mother-in-Law," starts with the company unnamed; over the course of the episode, Alex learns of the concept of "ajana," the unknown, from his mother-in-law and chooses it as his company's name.
Other mistake: Private Duke Slater's utility uniform shirt is different from the other Marines. Duke's uniform has square pocket flaps with the button exposed, an exposed button front shirt and the sleeves do not have button cuffs. The other Marines' uniforms have tapered pocket flaps with a hidden button, a hidden button front shirt and the sleeves have button cuffs. (00:05:00 - 00:06:00)
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.
Other mistake: In this episode, they have a leak in the roof. Yet, the house is a two story house with an attic. So it should not be able to leak into the living room. Also, when Carl and Eddie go up to fix the roof, Eddie falls through the roof and ends up on the living room couch. Again, two story house with attic. Should not happen.