Continuity mistake: In the scene where Parker is shown playing golf on the indoor golf course in RDA, the first time he hits the ball, there are two other balls lying on the course side by side. In the next shot, two are distant apart and in the shot after that, they are in their original position. (00:12:15)
Continuity mistake: AMP suit details such as the windshield wiper blade/arm as well as the grab handles on top of the cockpit appear and disappear throughout the film, depending on whether a CG model or practical prop are being used.
Continuity mistake: In the scene where Jake wakes up from his link and Grace asks him, "Is the avatar safe?" and he replies, "Yeah Doc, and you are not gonna believe where I am," her hand is on top of his shoulder. But as the camera angle changes back and forth her hand switches to the side of his upper arm and back to the shoulder without time to have made the move. (00:48:55)
Chosen answer: Jake and Neytiri were holding hands and Neytiri had her hair unbraided. It is also possible that when Na'vi mate, their appearance changes slightly in a way that only other Na'vi could see.