Character mistake: The protagonist says "You know, Croesus once said 'Count no man happy until the end is known'" but it's not Croesus uttering that line. According to Herodotus, Solon says it to King Croesus. (00:03:00)
Character mistake: A radio report refers to a character with two different police ranks with 15 seconds apart in the same broadcast - first as a Police Chief and a few seconds later as a Captain. (00:21:28)
Character mistake: Bart is sitting on a bench outside the hotel. After Detective Espada talks to the Mercer hotel manager/owner, he goes to talk to Bart. Bart has blood on both hands and lower left sleeve. Detective Espada is supposed to be investigating a fresh murder case that puts Bart at the scene, but he does not confiscate Bart's bloody clothes, conduct a gun powder test on Bart's hands to check for residue, or take him to the police station for formal questioning. Espada did not follow police protocol. (00:17:36)
Character mistake: Jean rolls, kneads, and flattens the dough a few times, repeating the steps to give the image of still preparing the dough. After the dough was flattened, it was well-shaped (round, higher, and more compact) then flat again. The way she was shaping the dough suggests she was making biscuits, but biscuit dough should not be handled that much (or the biscuits would be flat and not flaky). (00:18:00 - 00:19:00)
Character mistake: Dean told Laura that Fiona's toiletry case was in his bag because "She couldn't fit it in her carry-on, so I put it in my luggage." Laura (who had no reason to fabricate the story to her dad Felix) changed the details, which she couldn't know based on what Dean told her: "There were some of his co-worker's toiletries in his luggage. But she couldn't put them in her carry-on for security, so he offered to put them in his luggage." Unable to fit in isn't the same as "for security." (00:13:05 - 00:23:57)
Character mistake: Caseworker Jaylene recognized the man in the photo with Tulsa's biological mother (deceased for two years) but did not know if Tommy was Tulsa's biological father like Tulsa asserted. Jaylene also knew the proper procedures for placing a child (including emergency situations) and that she could lose her license - not to mention be putting the child at risk - by letting her stay with Tommy. Supervisor Kerry even warned Jaylene, but Jaylene left Tulsa with the man "assumed" to be her father. (00:07:05 - 00:12:35)
Character mistake: There are signs out front as the Spenglers arrive at the dirt farm. One of the signs is a call back to a scene in Ghostbusters 1984. In the scene, Ray quotes the book of Revelation: "And I looked, and he opened the sixth seal, and lo, there was a great earthquake. And the sun turned black as sack cloth, and the moon turned blood." When Finn Wolfhard reads it he misquotes the line saying "The sun became as black as cloth."
Character mistake: After the dodgeball game ends Jerry asks the referee if skyzone had a bar, but in the background he's already walking away.
Character mistake: The prescribing doctor or a nurse should have given Matt/Joey's mom instructions on the proper use of an oxygen mask, but she did not demonstrate this. She picked up the mask, put it over her nose/mouth, and immediately inhaled ONCE followed by removing the mask. About a minute later, she repeated these ineffective steps. Instead of inhaling the oxygen, she was most likely simply inhaling "regular air" in the room - she did not keep the mask on long enough to enable release of oxygen.