Revealing mistake: When the Lieutenant is explaining how her gun was in the victim's house, the camera pans behind Gibbs. Pay close attention and you can see a very faint shadow move across his back. Since we see there is nothing behind him on numerous occasions, it can only be part of the film crew.
Revealing mistake: During season 4 the same television clip of President Bush and VP Cheney disembarking Air Force One is used on the background television in the squad room. In some cases the clip is running and not in unison, on three of the televisions in the same scene from shot to shot.
Revealing mistake: Part 1 - As Tony eats his donut, and spills the jelly on his shirt, it's clear that (the actor) is moving his body to make that 'accident' happen as scripted. As the jelly begins to leak out, he doesn't move; because it doesn't fall as expected, he jerks suddenly, to make the jelly fall on his shirt. He stops moving, 'shocked' at this, holding the donut with both hands.Part 2 - The camera angle changes to 'behind' him, and he is only holding the donut with one hand.Part 3 - He then grabs at a napkin (just out of frame) to clean it off; the camera cuts to Ziva briefly, then back to Tony, who does not have any napkin. (TIME: Approx. 24:55-25:05.)
Revealing mistake: When Tony is telling Gibbs & Ducky that Abby got a hit on the dead sailor's fingerprints, Gibbs takes the file from Tony; the camera shows the file, which appears to be a legitimate profile sheet, but in the comments section, is the script that Tony just read aloud.
Revealing mistake: When Ducky and Gibbs are in the morgue examining the body of the girl found in the hotel, the camera cuts for a few seconds to the girl lying on the slab. During that shot, you can see her neck moving to her pulse (just after Ducky says, "There's some bruising on the sternum").