Continuity mistake: When Tony is working on the laptop in the van, the IP address shows as 934.554.32.3. Not only is that an invalid address, but when he enters Rhodes' credentials, the IP changes to 93.455.43.232 (also invalid). (01:05:45)
Revealing mistake: When Tony and Rhodes are on the oil tanker bunkered behind an obstacle, Tony realises his gun is empty and asks Rhodes for a new magazine. When Tony ejects the magazine you can see that it is actually an airsoft gun magazine; thus exposing that it is actually a prop gun.
Continuity mistake: Colonel Rhodes holds his pistol to the face of the Mandarin in a close up shot, then lowers it. The next instant shot later of Rhodes show him still holding the pistol to the Mandarin's face.
Continuity mistake: When Tony leaves the bar, his hands are cuffed behind his back. When he is shot at in the next scene after jumping through the window, his hands are somehow cuffed in the front of his body. (01:54:50)
Revealing mistake: When Tony is knocked violently forwards during the test of the Mark 42 armour, he somehow arrests his fall mid-air just before propulsors in his hands actually fire, because the effects weren't perfectly synced with the wirework.
Continuity mistake: When Tony is attacked by helicopters in his Malibu mansion, his right hand has a black wrap around it. After he gets buried by rubble underwater in the suit, his right armored hand detaches and grabs his bare right hand to pull Tony out from the rubble. Tony's bare hand no longer has a black wrap.
Character mistake: When Happy is in hospital, two bad things happen: One, when a nurse comes into the room, she injects a drug into his IV line, but she doesn't kink the line above where she is injecting, so the drug goes both down and up the line. Two, Happy's IV line isn't attached to a pump. The nurse manually fiddles with the flow rate of Happy's IV. But the fiddling leads to nowhere, as she doesn't look at the chamber where the drops come out - this is very important, as the IV bag can run out anywhere from 30 mins to 3 hours.
Continuity mistake: Just before Iron Patriot boards Air Force One he is shown with red illuminated eyes. Later when he enters the office onboard before he takes the president his eye colour changes to blue. (01:31:51 - 01:32:50)
Continuity mistake: The wound on Maya's forehead changes color, angle and position through the film.
Answer: With the release of Endgame, it is now fact that the Battle of New York took place in 2012.