Character mistake: When Sheriff Brackett is talking to Loomis at the food stand, he calls him Don. His name is Sam. Even says it in the subtitles. (01:19:35)
Suggested correction: He could possibly be saying "Doc".
No, he's definitely saying "Don." It's never been addressed, but I think it's an honest mistake with two people who have never met before and maybe an homage to Donald Pleasance, who played Loomis before.
It's hard to say, but it does sound like "Don." The sheriff says "doc" two times later in the same scene and those two times definitely sounds different than the first time. But I don't think it's meant to be a homage to anyone. I think it's just an actor who flubbed the word.
Character mistake: Jonesy says he read about Amber going to West Point. She was a Marine, and not in the Army, which is what West Point is for.
Character mistake: When LT. Col. Robert Neville's wife fails the eye scan and he's ordering the soldiers to scan her again, the soldier that escorts them to the scan point, and later to the helicopter mistakenly uses Will Smith's real last name. You can faintly here him identifying LT. Col. Robert Neville to another soldier as LT. Col. Robert Smith.
Character mistake: Roy says, "He thinks the wounds look self inflicted." But the doctor who said that was a female.
Character mistake: Alice shoots the henchmen, the black officer is attempting pull a gun from his shoe but in closeup his leg is white, then back. (01:06:25)