Why did she leave NCIS?

There is something that happened during the summer break between seasons. They're not telling us fans about it. Instead they give us a *beep* reason. I remember Pauley was even surprised a few days before filming began that something was going on coz Côte wanted out of her contract during the last minute. I also heard David was not impressed with Cote's behaviour/decision and how she handled the situation.

I just read a report yesterday (4/25/16) that she stated in an interview she didn't like the way they were treating the character. I don't know what specifically.

I'd have to guess she has the same concerns that people on the NCIS board have - she's Barbie/Mary Sue...

and kinda exists to be a romantic interest for Tony.