Factual error: While handling the ignition coil cable to the distributor cap, Joe Pesci tells De Niro that the timing chain needs adjustment in his truck. A truck of that year with an inline Chevy motor would not have a timing chain at all, instead this truck would be equipped with a direct drive timing gear. Even if it had a timing chain, it would be behind the water pump and a cover. It would have been a several hour job to replace, not possible to adjust it.
Visible crew/equipment: At the beginning of the film when being rescued from the quicksand you can see someone's legs and hand behind the horse, holding it. (00:10:00 - 00:11:00)
Continuity mistake: When Elton and John Reid are kissing in the cupboard John's hand keeps changing between shots. John's hand rolls down Elton's chest, then the next shot it's on Elton's cheek, the next shot he takes his hand away, then the next shot his hand is by Elton's mouth and Elton pretends to bite John's thumb.
Continuity mistake: After Mick Mars has Nikki and Tommy kick the guy out with the guitar at his audition, the guy leaves and cries through the door. Nikki is standing by the door and looking nearly straight forward as the guy leaves, but then the camera changes angles and suddenly he's looking more to the side towards the door. Also his arms are a little higher up holding his guitar.
Factual error: During Lee Iacocca's slide presentation to Henry Ford II in 1963, there are two slides that reference James Bond. One shows him standing next to the Aston Martin DB5, which made its debut in "Goldfinger" in 1964, and another shows a still image from "Thunderball", which was released in 1965.
Character mistake: After the smoking seminarians joke, Bergoglio replies to Pope Benedict 's phrase about being alone "Isaiah 41, chapter 10." It's not chapter 10, but rather verse 10, of chapter 41. (00:52:50)
Factual error: As well as the sergeant's stripes on his cuff, Sergeant O'Neil wears three pips on his epaulettes, which would indicate a much more senior rank and would not be worn together with the stripes.
Factual error: The scenes set at Wrestlemania XXX (2014) were filmed at a RAW show in 2018 - fans are visible in the background wearing wrestling merchandise more recent than 2014.
Factual error: Eve Curie is shown as having been born before the Curies are nominated for the Nobel Prize in physics, which they eventually won in 1903. However, Even Curie wasn't born until December 6th, 1904.
Continuity mistake: The front view of Sheriff Garrett [Ethan Hawke] while he is talking to Billy shows a stone-walled well between him and the cabin door, but there's no well visible in the rear view. When Billy walks out with his hands up, there appears to be a well to his right (where the horse rail should be visible), but there is no well when Sara and Rio exit the cabin. (00:14:04 - 00:15:10)
Factual error: There is a modern digital electric meter in the record store - not what it would look like in the era of the movie.
Continuity mistake: On the subway, behind Mr. Rogers, the sign showing the train's destination changes.
Factual error: In 1915 Tolkien was commissioned as a Second Lieutenant with the Lancashire Fusiliers. He (plus various other officers) is constantly shown in the film wearing bright metal cap badge, collar badges and shoulder titles on his Service Dress tunic and greatcoat. However, in the Lancashire Fusiliers officers did not wear shoulder titles on their SD tunics/greatcoats, and their cap/collar badges would have been in a darkened bronze finish, not bright metal (which was for Other Ranks and NCO's).
Other mistake: Judy is singing on stage with some showgirls. She is singing into a wired microphone. At the end of the song she twirls around twice, but the microphone does not appear to get wrapped around her. (00:49:35)
Factual error: Three details were omitted on the Miller's car's license plate: the month was missing in the upper left-hand corner; a "15" (2015) sticker was missing in the center of the plate; and, "Show Me State" was not written at the top below "Missouri." (00:16:46)
Other mistake: Elsa Brecht is holding an official piece of mail sent from the Coconut Grove Hotel in Miami but it's postmarked Orlando, Florida. There's no legitimate reason the mail would be postmarked Orlando when Orlando is 235 miles from Miami. (01:24:16)