Continuity mistake: After Andi's mic-drop moment interrupting Miles ' speech, Claire runs after her. Birdie is biting her fingernail, with a different position in close-up (her other fingers are up in the wider angle, lowered to let you get a better view of Kate Hudson later). (00:36:25)
Continuity mistake: When Birdie makes her way poolside she smiles at Lionel; in her slo-mo approach her left hand holds the foulard, but in the next shot she is holding the brim of her hat. (00:27:50)
Factual error: A major plot point revolves around the fact that the police and medical staff can't reach the island because the "Pisceshite" dock is non-buoyant and they need to wait for the low tide. While we do not know exactly where the fictional island is, other than the fact that it's 2 hours off the coast of Greece and Blanc mentions (correcting Miles Bron) that it's in the Aegean sea and not the Ionian sea, it's fair to say that the tides in that area of the Mediterranean are negligible, not reaching even a meter in very selected spots, and averaging at mere centimeters. It's nothing that would impede navigation and police or medical team to arrive. (01:02:30)
Continuity mistake: In the flashback, Helen tells Blanc as he kneels to tie the shoelace "Duke and Birdie, I think they're onto me." Notice the sunglasses poking from the top of the frame, and the right hand that moves away showing that the shades are in her left hand. But it cuts back on her in a shot from the waist up and her glasses are in the right hand. (01:25:35)
Continuity mistake: The night before the boat trip, Blanc tells Helen "This is your last chance to back out"; his forearm for just that shot is on the back of the bench. (01:24:55)
Continuity mistake: Andi topples the shelf and various books fall off scattering on the floor. In particular, "The Innovator's dilemma" is propped on top of a different open book. In the close-up where she pulls the napkin out of it, the book shifted without anyone touching them. (01:23:30)
Continuity mistake: When Helen shows Blanc the notepad where she drew the Clue-style tab, the letters are drawn in a different way from the close-ups (most obvious hint; the M for motive does not touch the grid). (01:24:20)
Continuity mistake: Debriefing Helen at the restaurant the night before the impostor game begins, Blanc tells her how to behave on the boat. Her hands are off/on the table between shots. (01:18:45)
Continuity mistake: At the beginning of the retelling of the story, Blanc holds Helen's phone in his right hand, and yet the close-ups are of a left hand. (01:13:40)
Continuity mistake: Throughout the conversation with Helen on Benoit Blanc's terrace, her facemask switches position between two distinct spots on the table. (01:11:00)
Continuity mistake: Blanc says "Where's Duke's phone?" holding his wrist in the closer angle, but his hands weren't there in the previous wider view. (01:04:05)
Continuity mistake: Duke falls back on the glass table and spasms. His left hand is on top of the right one, but as he rolls over the hand switched place. (00:59:50)
Continuity mistake: Miles fixes himself a drink saying "fake it till you make it." He then joins the others, but look at Birdie Jay and her assistant; completely different poses between shots - Kate Hudson is even dancing with and then without her massive glass. (00:58:40)
Continuity mistake: Miles seems to have pep talked his friends into staying for the rest of the weekend after the momentary crisis brought by the premature end of the murder mystery. He says "You're staying" to Lionel, who is holding his glass with both hands, then suddenly with one hand, the other hand being on his knee. (00:58:25)
Continuity mistake: When Claire drunk-staggers down the steps after Andi left the party, she holds chips in her hand, or does not, depending on the camera angle. (00:57:10)
Continuity mistake: Andi leaves after Duke's words. He walks down the steps, and Birdie looks at him, drink in hand. Depending on the shot, the left hand isn't or is on the straw. And a moment later Miles and Blanc join back the crowd, and her hands switched place, drink supported by the left and right hand on the straw. (00:56:55)
Continuity mistake: Addressing "the elephant in the room", Claire springs up from the couch and flailing her arms she shouts "Nothing about any of this is fair." Notice in this full view of the room that her jacket is off the pillow it was resting on in the closer angle. (00:54:45)
Continuity mistake: Duke tells the others that he is leaving the next day. His girlfriend, on all fours, seems to complain. Duke makes a weird noise, and then in the shot from the top he says that she can stay. However, his grip on the glass is different. (00:54:00)
Continuity mistake: Lionel and Duke are looking at his phone. Birdie walks behind them saying "Thank God for Benoit Blanc." She passes twice the same spot, Lionel each time holding the rim of the glass in a different way. (00:53:50)
Continuity mistake: After claiming his iPad, Blanc cautions Miles that "for at least one person on this island, this is not a game." His grip on the top of the chair changes between shots. (00:52:10)
