Factual error: Following the blowout, Sara's phone is shown several times as being connected to Wi-Fi with a full Wi-Fi signal. Being in the middle of nowhere, surrounded by hills, it's highly unlikely there would be a public Wi-Fi connection for her to connect to.
Continuity mistake: During the initial briefing, the digital clock initially points the time pretty accurately, but then gets stuck on minute 56 for way too long; it's at 12:56:35 when they whip out of the drug lord's folder, 20 seconds of dialogue elapse till the clock is shown again at 12:56:47, another 25 before it gets to 12:56:55, and about 40 seconds before it gets to...12:56:56. And barely 30 seconds pass before Estrada arrives, at exactly 1 o' clock. (00:12:30 - 00:14:30)
Factual error: Will's Range Rover has a rear New York license plate but not the required front plate. (00:08:25)
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)
Continuity mistake: Alison is saying goodbye to her parents and she is wearing a long kimono. As she walks into her bedroom she is no longer wearing it, and then picks it up off her bed and puts it on. (01:07:05)
Continuity mistake: During the Memorial Day toast, Katie's hand is on and off the glass between shots. The level of wine in the glass also changes inconsistently. (00:12:20)
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.
Factual error: When the bank robbers pull the money out of the vault, they claim all the cash is from 1982. Yet most of the bills have large faces, which was introduced into rotation in 1996.
Revealing mistake: The bartender (Kateryna Korchynska) offers Ethan two lattes on the house. She hands them to him, and he walks out. No opacity from the liquid can be seen inside the plastic cups, and when he is moving away from the counter he leans forward quite a bit, showing the inside of the cups, squeaky clean. (00:08:00)
Continuity mistake: Lynn Jackson collects things from the desk and looks at George Pierce, who tells her "I'll talk to him", clutching his smartphone to his chest. Next shot and his arm is down his side. (00:18:10)
Deliberate mistake: The front passenger's side mirror [driver's side is on the right] is parallel to the screen/camera yet there is a perfectly clear image of the passenger's face looking into the mirror. (00:00:38)