Continuity mistake: Maddie says she wonders what Kelly would have been like and she has her hand on her shoulder. Camera changes and her hand has gone. (00:11:15)
Continuity mistake: When Maddie turns the photo album round, its position changes between shots. In the first shot she is holding it by the top of the album, as shown with a brown photo being away from her hands. Camera changes and now she is holding it by the bottom of the album and her hand is on the brown photo. (00:09:40)
Continuity mistake: Maddie puts the magazine down with one hand while holding the photo album in the other, camera changes and she's got the photo album in two hands. (00:09:20)
Continuity mistake: Abby takes a picture of McGee and the picture is displayed on the screen, however the TV behind McGee has a different picture in the photo to what it is when we see Abby take the picture. (00:06:15)
Continuity mistake: As Tony surfaces, Maddie's head is leaning to her left, then right then left all between instant cuts. (00:01:10)
Answer: I hadn't seen the backdoor pilots yet but while it wasn't explicitly stated, at least onscreen, I heard somewhere Vivian got either fired from NCIS due to jeopardizing a case, got resigned from the agency, or transferred to the FBI.
Raykvega423