Continuity mistake: The broom (?) handle that was sticking out of the pile of plastic was leaning into the corner of the empty swimming pool. At a more distant view (opposite end of the pool), it should have been visible but was not. In later views, the handle's position varied - straight up (not diagonal) and leaning in a different direction. (01:09:19 - 01:11:44)
Other mistake: During the driving scene in the woods with the Bronco, at least two shots are reused twice.
Continuity mistake: The movie opens with an American Football match; look out for the girl wearing number 6 for the red team, Molosses, who has mid-length locks of straight reddish hair coming out of the helmet, down her back. When a touchdown is scored and celebrations begin, number 6 takes her helmet off, revealing the face of the protagonist, Karidja Touré, who has long black hair in braids. (00:01:20 - 00:02:40)
Other mistake: During the dinner scene we see Finn pour Newgate a drink. Newgate then goes to drink from it when Eliza kicks him so he spills it. However due to the width of the table this should be impossible.
Continuity mistake: After David hits Hugh he gets a wound on his mouth which gets smaller the next day.
Factual error: During the Hungnam evacuation scene in December 1950, a U.S. Army Captain is using a radio handset. The model he uses is the H-250, which was introduced in 1987, over 30 years after the Korean War.
Continuity mistake: Master Lui at his first appearance in the movie kills the traitor slicing his throat with burning tongs which he points right away at the eyes of the protagonist. Sammo Hung's grip on the tongs changes between shots. (00:11:00)
Factual error: As the marchers start through the streets before they gather at the Edmund Pettis Bridge, they pass by a shop with a Pepsi sign. The Pepsi logo, however, is from the 1980s-1990s.
Factual error: In the opening scenes where Margaret drives to San Francisco, her car is an early 50s Meteor. Meteors were a Ford Motor Company brand just above Ford (a bit like Mercury) but were sold only in Canada. Meteors often were only rebadged Fords, like this early 50s model. The rest of 50s and 60s car choices in the film seemed perfect.
Continuity mistake: Rancer was shoving dinner rolls into his mouth, demonstrating his competitive eating ability/skill. He still had some in his mouth, but after he ran his hand over his mouth, there suddenly was no sign of any food in his mouth. (00:16:10)
Factual error: When the Germans come to the town a tank rolls through the picture. The first shot shows the tracks, then the whole tank is shown and one can see the tracks again. The turret suggests a Panzer III (which would be accurate for the time). It appears however that the tank is a modified Russian T34 or T55 or something as the road wheels are too big for a Panzer III. (00:13:00)
Continuity mistake: Kevin Shepherd pulls over in front of her fiancee's dad. It's still a wide angle, but you can see distinctly both her and his left arm stretched forward; she is looking at her engagement ring, he has his hand on the steering wheel. Before the camera cuts away though, he lowers his arm; it is not acknowledged in the new shot, where both have still their left arm forward. (00:03:35)
Factual error: The streak ended in '04, but at the beginning of the movie the seniors talking about their last game have letter jackets with the year '05 on the sleeve.
Character mistake: When Jesperson imagines himself as a Mountie his uniform is completely wrong and is not even the right colour. As it was his ambition to join the force and he has photos of RCMP officers in his cab, it seems unlikely that he would imagine himself in a completely incorrect uniform.
Suggested correction: It's not a character mistake, for the reasons stated; it's a clear factual error from the filmmakers.
It's a character mistake since it's his imagination and, as you stated, it's not something the character would get wrong.
Character mistake: At the end of the movie, when Jaggu is listening to the sounds recorded by PK, the audio contains the question which she asked, "Tumhare planet pe sab aise hi hote, bade kan wale?" but does not contain the answer which PK gave, even though he was sitting right there. This seems to suggest that PK did not exist in the real world.
Factual error: In a scene where Kat is flying to or from Northern California for college, in the background through the window on the plane one can see a commercial jet which has the winglets of a narrow-body Boeing, which were not introduced until 1998 on the Boeing 737 NextGen, rather than "wingtip fences" of an Airbus which were in use as early as 1985. Eve disappeared in 1988 when Kat was 17, so this would have been 1993 at the latest, when Kat would have been expected to have graduated from Berkeley. In the movie, it is suggested that this was just 2 years after her mother disappeared, so this would have been not later than 1990-91.
Continuity mistake: The appearance/structure of the ground-level components of the well changes several times. In the first view, the unit is mostly gray and rusty with one vertical white pipe. When Ernest is pumping, half of the horizontal pipe is also white and clean. In the rear view, the vertical pipe is brown and rusty. Some mud spurts out of the spigot, but the spigot is clean, dry, and white in the front view. (00:05:10)
Revealing mistake: JR is in the weapon container of the crazy dealer, who passes him some of his goods. JR ends up holding in his right arm a MP5K and an M4A1, which combined are about 5 kilos, but then he passes him an M60 Machine Gun, which weighs over 10 kilos and that the relatively diminutive protagonist just handles throughout the scene gripping it with his left hand and making no effort whatsoever. (00:25:20)
Continuity mistake: During the early part of the movie, the left rear door of Doc's car is dented. For the rest of the movie, the dent is gone.
Factual error: While Evans and Eve are still in Grand Central they overhear an announcement which states "According to Port Authority policy This station will be closing for the evening." Grand Central is not part of the NY/NJ Port Authority. Also Grand Central is a terminal, not a station, as trains do not pass through Grand Central, they enter and turn around.