Continuity mistake: All the characters showed up for Miles on the beach by the 'Pisceshite' pier, and Duke asks "when's the murder mystery start?" In the reverse angle Peg holds the Luis Vuitton-bagged dress across her back in a different way, and the group with Birdie and Lionel is positioned differently to better fit the framing of the shot. (00:21:15)
Continuity mistake: In her introduction, Janelle Monáe is tapping nervously the card on her lap, holding it in a different way between close-up and wider angle. (00:10:30)
Factual error: Birdie tries to use the tune recognizing app Shazam speaking to the wrong device. When she does that, the TV in the background plays footage from CNN, with the coronavirus epidemic, featuring Dr. Fauci. However, in that particular part of the scene they also show a map of the US that displays the states with no mask mandate. The chart can't be a May 13, 2020 one (supposed date of the scene), since it shows the situation at the end of the year. Several states in white like Washington, Nevada, Oregon adopted it only in the summer. (00:08:20)
Deliberate mistake: Being merely a comedy bit it does not have to make sense, but Dave Bautista's mom solves the puzzles without even being able to look at them from her sitting spot. You could argue she somehow could figure out the nature of the compass from the first glance she took solving the stereogram, but the Fibonacci sequence was not on display yet. Also, Duke joins the call saying that she "did something" to the box, it "opened up" and she "broke it", but actually he never saw any of that that, the puzzle was already open in the background before she'd even tell him there was a delivery.
Continuity mistake: When Peg calls Birdie out on the use of the word "jewy", she leans against the puzzle, holding the phone too. Her friend complains about the "wokeness" of everything, and Peg is gone entirely. (00:03:45)
Continuity mistake: Lionel discusses with his fellow tech people the various crazy ideas the boss faxes in the middle of the night. There are several fax sheets rolled on the table throughout the scene. When he mentions the "Crypto Kids app", some sheets have been straightened out and lie on top of the rolled ones, but when the delivery person calls, there's nothing on top of the paper roll. (00:02:15)
Continuity mistake: In the flashback, Daniel Craig reacts to the gunshot that fell Helen hunching in two different ways in the two separate shots. (01:44:00)
Continuity mistake: When Birdie's assistant Peg brings in the box, her hands are at the bottom of it and immediately on it in the next shot. (00:03:15)
Continuity mistake: When in the flashback Claire mentions the Hindenburg, her hands go above/under the water between shots. (01:28:45)
Continuity mistake: Lionel states that he saw Miles drive away with his right hand raised, left hand in the close-up. (02:10:00)
Continuity mistake: Miles removes his hand from Andi's shoulder after her icy stare twice in two separate shots. (00:24:05)
Continuity mistake: Speaking to Miles for the first time, Blanc foes for a handshake but Miles' sunglasses switch hands. And when Blanc sidesteps to let him face directly Andi, he lowers his arms, but they are up again in the next shot. And then, Edward Norton's right hand gives a thumbs up in the reaction shot, with the same arm he just lowered before. (00:20:55)
Continuity mistake: Duke mentions Benoit Blanc 's presence to Miles for the first time on the beach, and at the same time his girlfriend is walking away from the eccentric billionaire. The next shot does not properly follow; Dave Bautista 's hand is back on top of his hat, Whiskey and Ed Norton 's arn positions don't match. (00:20:45)
Character mistake: Miles is playing on the beach a tune that Birdie Jay recognizes instantly as Blackbird by the Beatles, and Miles flexes saying that it's the exact guitar Paul wrote it on. That'd be difficult though, since it's a right handed guitar, and McCartney plays left handed (albeit he can play right handed too). You could argue that this is one of the hints that Miles is not very smart. (00:20:00)
Continuity mistake: When Birdie hugs Miles on the beach, his shades are in a different position by the guitar headstock between shots. (00:19:50)
Continuity mistake: During the scene on the pier that sets the movie in Greece, in most close-ups on Benoit Blanc you can see lines tied to both the bitt and the metal ring behind him, while the other angles show no cable or ropes secured and nothing on that side of the pier. (00:13:25)
Continuity mistake: The Efficient Man portrayed by Ethan Hawke tells the guests to remove the masks. Birdie Jay removed it already in the wider angle of the pier, but she removes it again in the next shot when he shoots her in the mouth. (00:16:20)
Revealing mistake: Dave Bautista announces that he has arrived. There's a close-up of the kickstand, and you can actually see scratches on the asphalt from previous takes (spotted also by Rian Johnson himself in his video breakdown of the arrival scene for the Vanity Fair youtube channel). (00:15:10)
Continuity mistake: Hearing his name, Claire asks Benoit Blanc if he's THAT famous detective, the one who solved "the thing and the thing." In the shot where Blanc admits to indeed having solved the thing and the thing, you can see that she pulls up the facemask, but her hand has yet to come up and touch it in the next shot. (00:14:50)
Continuity mistake: On the pier, Kate Hudson calls Blanc "Stranger danger." The Greek porter Nikos makes a comment about it, hands on a suitcase, and Lionel is carrying a bag next to him. Brief reaction shot to a masked Daniel Craig that denies that, and not only Nikos' hands switched position and are on a different suitcase (which could have happened even if it's not what the posture implies), but Lionel is also bringing again the same bag. (00:14:25)
