Factual error: They are filming in Brussels and the leaving Mercedes 190 has indeed a Belgian license plate. But it is a fake plate that has a mistake... It shows 1-N82-63X but a license plate in Belgium has always a combination of 1-xxx-123 where the first part always has letters and the second part numbers. Numbers and lettters are never combined. Also it is missing the mandatory sign to prove authenticity. (00:48:30)
Factual error: Though the movie is playing with historical events for "laughs," it should at least be pointed out for the record that Queen Victoria died in 1901, and the Titanic didn't launch until 1912 (and its construction didn't even start until 1909). So, obviously, there's no way Victoria could have toured it before its maiden voyage. (And the movie acknowledges that it's supposed to be THE Titanic since it shows Moriarty reading a newspaper reporting that it sank, to say nothing of the Billy Zane cameo).
Factual error: Max could not have been accidentally shot when Annie drops the revolver. She dropped it when she was startled by firing it into the ceiling so the hammer would still be sitting on the spent/empty shell casing. The trigger or hammer must be pulled back in order for the cylinder of a revolver to rotate to the next live chamber.
Factual error: The plane used in the film to take Juliet back to London towards the end of the film is a replica of a Dakota C-47. She is painted with black and white "invasion stripes" on both the upper and lower surfaces of the wings - approved in May these were only widely put into use for D-Day in June 1944. After one month the upper surface stripes were ordered removed, and by the end of 1944 they were ordered completely removed. By 1946 when the film is set they would have been long gone from any serving aircraft still flying.
Factual error: In the police shoot out scene, you can see that the plate carriers the actors are wearing are really empty. Brolin sticks his hand into Forsing's vest after he was shot, the vest easily folds away. You can also see in various shots how theirs vest bend with their bodies, in a way they wouldn't if they had plating in as they should to protect from bullets.
Factual error: When Mary and the children go to the bank the long shot of the bank shows a statue that was not erected until 1994.
Factual error: The blue license plate with yellowing lettering has not been used in Pennsylvania since 1999. The date on the inspection sticker on the front windshield of a vehicle was "7/17" (July 2017 expiration date). A 2017 Pennsylvania plate was (and still is) white in the middle with a strip of blue along the top and yellow along the bottom. (00:19:52 - 01:19:30)
Factual error: When Buster joins the card game in the saloon, he looks at the hand of the player that had just left. Given the circumstances in the saloon, the cards cannot be spot clean and white as fresh snow. Also, they seem to be plastic cards, which did not exist yet back then.
Factual error: The robbery flashback scene is at least 15 years previous to the main story, placing it circa 1953. The big lettering on the armored car uses Helvetica font, which did not exist until 1957.
Factual error: Sherman prints a gun through the hospital's 3D printer. We see the gun, the cylinder, and 6 bullets. But if bullets are printed too, they still would need to contain the gunpowder, and the 3D printer construct shown there looks made out of a single kind of material, plain looking, surely not the product of a wonder machine that'd be able to recreate the complex chemistry required to make working bullets it was not even designed to do - in fact they look like suppositories, with no division at all between primer, casing, etc.
Factual error: Simon receives an email notification at the dinner table from Blue on his cell phone. The cell phone screen indicates that the time is 3:20, which is inaccurate for a mealtime because it is already dark outside and crickets are chirping when he excuses himself to go outside to get some air. (00:28:10)
Factual error: The vehicles in the convoy are supposed to be armored since the bullet fired by 50 BMG was absorbed into the glass. First off the vehicles are standard, not up armored since the windows are standard factory and not thick ones used in up-armored cars. The highest rated armored car is B7 which will stop armor piercing not 50 BMG. Also, the windows completely shatter after being shot out; armored windows will never shatter, they stick together and chip off. (00:03:00 - 00:05:00)
Factual error: Cat Rivers is flying the R44 helicopter from the left seat. The R44 is a single pilot helicopter fitted with dual controls. Two collective levers may be installed (the left is removable) but the cyclic control is not of a conventional nature. This comprises a central stick terminating in a pivoting T bar, which only allows one of the pilots at any one time to control the cyclic with the hand grip in the 'normal' position. The R44 is normally flown from the right seat; it is possible to fly from the left seat and instructors regularly do so. Students and low experience pilots would normally only fly from the right seat, and are discouraged from flying from the left seat when with friends. This is because of the unusual cyclic control configuration and, to some extent, the different instrument scan and visual references for hovering when flying. (00:14:40)
Factual error: The opening scene shows Cassie and Bryan booking their holiday on a laptop. The dates that they book the holiday home are between May 5th 2018 and May 12th 2018, which means the movie is set in 2018. But later in the movie, when Cassie finds the video of Bryan with the two women on his phone, the date is listed as "Sunday, May 7", and May 7th 2018 was a Monday, not a Sunday. (00:01:05 - 01:10:55)