Factual error: Dr. Boxer is told the experimented upon baboon died. He asks that an autopsy be performed. Autopsies are performed on humans. A post-mortem examination on animals is called a necropsy. (01:01:45)
Continuity mistake: Maddox has blue eyes as a teenager and dark brown eyes as an adult.
Continuity mistake: At the prison visiting "Uncle Sally", Dickie sets a box of matches on top of his cigarettes. A little later, the matchbox is behind the cigarettes and the cigarettes are angled about 45° more away from the ashtray. (00:48:12)
Continuity mistake: Leonardo DiCaprio's phone is shown attached to his car dashboard. He gets out of his car, all the while, looking up toward the sky. The next scene shows him grabbing his phone from his pocket while standing outside his car. (01:36:06 - 01:36:56)
Revealing mistake: When Teddy's Cadillac Seville is blown up, you can see that the engine, transmission and catalytic converter have all been removed.
Continuity mistake: Rudy sets the snow globe at an angle to the right of the clear glass tree. The camera shifts to Clarice and back. The snow globe is gone, but the salsa bowl moves to the left and fills in the space. The snow globe and salsa bowl are back in place, indicating that the discrepancy is not due to Rudy handling the globe off-screen between views. Also, the large snowman figurine with the tall hat is visible in front views of Rudy, but not in rear views. (Other glassware appears to vary.) (00:21:35 - 00:22:00)
Factual error: Sassoon's Military Cross medal is shown ending up thrown in the Mersey and sinking. In his own words from "Memoirs of an Infantry Officer", published in 1930 - "I ripped the MC ribbon off my tunic and threw it into the mouth of the Mersey. Weighted with significance though this action was, it would have felt more conclusive had the ribbons been heavier. As it was, the poor little thing fell weakly on the water and floated away as though aware of its own futility."
Deliberate mistake: Evie digs a box out of the greenhouse dirt, but no dirt falls off the box, and the box is clean when she moves it onto her lap. (00:09:00)
Continuity mistake: The way Franck's scarf was wrapped and tied around his neck changed from when he was sitting on the steps (wrapped around a few times with ends folded under) to when he was standing along the guard rail (a loop down the middle of his chest). (00:15:09)
Character mistake: Immediately after kissing (through masks) and having close contact with JJ, Valeria removed her protective mask and went to check on her sick/crying child. Valeria was clicking her tongue, kissing her child on the face/head and putting her hands around the child's ears/hair. Valeria did not take appropriate preventive measures for contracting and/or spreading COVID-19. (00:18:40 - 00:19:29)
Other mistake: The issued sidearm for the Spanish National Police is the H&K USP 9mm Compact, which has a capacity of 13+1 bullets, and the Civil Guards' is the Beretta 92fs/M9, which is a 9mm and has a magazine capacity of 15+1 bullets. As of 2020 the Beretta is being phased out for the H&K USP C. The police officer fires a total of 5 bullets from his Beretta then the slide locks back because its dry. He has no magazines for reloads either. I highly doubt the Spanish police issues 5 bullets to their officers. (00:33:00 - 00:35:30)
Factual error: The initial police scene takes pace 20 years ago. The present year is 2021, so 20 years prior would've made it 2001. The police Chevrolet Tahoe at the opening scene of the film was only made from 2007 and up. (00:05:40)
Deliberate mistake: The angle of the light coming from the film projector (which was up high on the back wall) was too high to actually project onto the screen across the room. Also, people were standing in front of the screen and should have been blocking part of the projection and have light on their backs but did not. The screen operated more like a DVD player on a TV. (00:35:20)
Revealing mistake: Ronnie is shown looking through the vertical-rectangular window of a brown door to Joey's hospital room. His eyes are angled to his left, indicating he is looking toward the person in bed to the left of a double room. When Ronnie is standing next to and facing the man in that bed, there's no door with a window behind him that he could have been looking through. There is a windowless white door on an adjacent wall. (00:00:40 - 00:03:42)
Revealing mistake: The "unnatural seam" (line) across Jimmy's forehead and beyond - as well as the overall appearance of his head - indicates that he is NOT "naturally bald"! His "fake" bald head was not put on nearly as well as those seen in numerous other movies. [The actor playing the character does not have much hair in real life, but he also doesn't have that artifical line across his forehead.]. (00:07:13)
Revealing mistake: When "Snowball" is sleeping on Lena's bed, it is obviously a "stuffed double" (stand-in). Snowball is usually partially hidden behind the dog (so breathing doesn't need to be shown/mimicked). The failure of Snowball to make even a slight movement is a giveaway (e.g, no ear movement when Lena starts talking), but even the stuffed lion, in itself, is not a very good replica - it simply looks fake. (00:33:44 - 00:48:20)
Factual error: James called the "Washington Board of Psychiatry" to file a complaint against Dr. Clark (Philip). Complaints (which need to be WRITTEN) against medical doctors are filed under a State's Medical Board, which would be the Washington Medical Commission in this case. Washington has a Board of Psychology and there is a Washington Psychiatric Society, but there's no "Washington Board of Psychiatry" per se (and even if there were, a complaint would still be filed with the Medical Commission).
Continuity mistake: After Diane lit and switched her cigarette to her right hand (and off-camera), most front views of her left arm showed it in front of her, along her stomach, but rear views showed her holding the cigarette in her left hand with her arm more perpendicular to her stomach. Whether her left elbow was fully on the table or over the edge also varied numerous times. (00:08:00)
Revealing mistake: When Julie is running around the city whilst all the extras are stood frozen, there is a moment where she is walking next to a small park, before beginning to turn right and run down a road. Once she runs onto the sidewalk after running down the road, two girls can be seen stood on the same sidewalk holding hands. The girl on the right can be seen moving her right hand ever so briefly, even though the extras are all supposed to be standing completely still. (00:54:35)
Factual error: During the escape from the farmers market a red London bus is in the background. Those busses aren't used in Gloucester.