Character mistake: Early in the film, Sister Paxton reveals that she wants to come back as a butterfly after she dies. Reincarnation is not a tenet of Mormonism.
Character mistake: In his opening prologue, Burt says the Graboids have been contained to the Northern Hemisphere, showing a map highlighting the Graboid attacks of the first film in Nevada and the second film in Mexico. However, it overlooks the Graboid/Shrieker attack in Argentina, in the Southern hemisphere, shown at the beginning of Tremors 3, an incursion Burt personally put down. It's not like it was classified - characters in that movie talk about it being reported by CNN, and characters in the Tremors TV series talk about it as well. And it's not like Tremors 3 is no longer canon, since Burt makes two references to being swallowed by the Graboid in that movie (which also becomes a plot point in Tremors 6).
Character mistake: When Marisa leaves the diner, you can see the door has a "Push" tag. However, the door opens inwards, and in fact to go outside she has to pull. (01:08:00)
Character mistake: Set in Texas, the Sheriff threatens the wrongdoer with the gas chamber. Executions in Texas at that time were all by electrocution, namely by "Old Sparky," the electric chair. Texas has never used the gas chamber for executions.
Character mistake: Sally and Franklin's last name is Hardesty, but for some reason Franklin refers to their old home as the "Franklin place."
Character mistake: In the scene where Maggie tells her sister she is pregnant and how far along she is in her pregnancy, her sister says the child will be a Gemini, just like Einstein. Einstein's birthdate is March 14th, making him a Pisces. Lisa also mentions that Shirley Manson from the band Garbage is also a Gemini, when in fact she is a Virgo.
Character mistake: Remy mentions that the insects are part ant, cockroach and termite. She dismisses the mantis side, which allows it to mimic.
Character mistake: In the highlighted newspaper article entitled 'DeFeo Son Accused' about the killings, the first sentence of the article ends with two periods. Also, in the 3rd sentence, the word 'psychiatric' is spelled "psuchiatric" with a 'u' instead of a 'y'. (00:01:05)
Character mistake: It doesn't occur to our heroes (admittedly kids) that you don't need to understand German at all in order to read it out loud. It's arguably easier to read than English! The only inscrutable letter would be "ẞ" but Scary German Guy's right there for help. (True, this is essentially what they end up doing in the end, but they still come about it through a "you don't need to be of age to be a virgin" realization rather than the even simpler "you don't need to know German.").
Character mistake: When Joan is searching the web looking for information on what monkeys eat, there is a section on the screen that reads "The diet of monkeys varies form fruits, leaves." Obviously the correct word for this sentence should be "from" not "form." (00:36:21)
Character mistake: Given Billy still remembered and recognized him it seems strange Kate doesn't when she mistakes Daffy for Gizmo.
Suggested correction: Billy spent significantly more time bonding with Gizmo in the first movie - days and days. By contrast Kate had very little actual time with him.
Character mistake: Tyler said, "Charlie says you're [Ben] gonna tell your folks that you got that girl pregnant this weekend." "This weekend" is a misplaced modifier. Ben didn't get the girl pregnant this weekend; Ben is supposed to tell his folks this weekend that he got a girl pregnant. (00:22:15)
Character mistake: Reina asked Cory if they could "do that thing" because it was helpful for her medical school training. Reina then put a raw slab of steak/meat across his forehead and made slits in the meat as well as jabbed at it. A medical student studying to become a brain surgeon should know about and practice the safe handling of raw meat. (00:23:10)
Character mistake: Marjorie's supervisor said the police found Nathan "torturing an animal [dog], there was a struggle and he assaulted one of them." Marjorie then asked, "Is he violent?" Her supervisor replied, "I have no reason to believe so. I mean, he did resist arrest, but that's probably out of fear" and the mental health team said there was "no obvious psychopathy." Social workers/mental health teams should have assessed cruelty to animals and resisting arrest as indicators of potential for violence. (00:03:55 - 00:04:30)
Character mistake: When Michael goes to the antique shop, the sign out front is spelled wrong; it reads "anitques."
Character mistake: There's a note from "mother" on the wheel at the diner. Right beside it is an order with the wrong total. 2 hamburgers for $1.95 each. 2 fries for 90 cents and 2 drinks for 90 cents for a total of $5.70. The waitress put $3.70 for the total.
Character mistake: Nolan said, "Everybody knows that no sharks swim in freshwater" and Spencer said, "They don't come into freshwater", but there are freshwater sharks (e.g, river sharks) and bull sharks (not true freshwater sharks) can survive in saltwater or freshwater. Jacob Harper (National Aquarium) pointed out eyewitness accounts of sharks swimming up the Mississippi River and "bull sharks have kidneys that recycle salt" but did not mention the glands near their tails that help keep salt in their bodies. (00:08:08 - 00:29:50)
Character mistake: When John meets his clone in the rundown house he lives in, the clone has a British accent and tells him his story. John has an American accent. When the real John tells him "I'm not like you, I had a wife, a family, a daughter" he mistakenly uses a British accent.
Character mistake: When Annie is in the red truck, she says that she'll be cooking for ten staff. When Alice goes to the beach, she tells Bill that everyone has arrived except for Annie. Even if she had arrived, there would only be eight of them: Christie, Annie, Ned, Brenda, Jack, Marcy, Bill, and Alice. Two shy of what she told the truck driver.
Character mistake: When searching the database for the missing girl, they find her and it says missing since 7 January 2021. When Caleb read it, he says "missing since February..."