When the team is in Abby's lab Tony has a blue drink in his hand. Abby takes the drink away but it is now red.
There are several grammar and spelling changes between the two shots when McGee is typing. Some examples are Gat, Was and deser in the first shot which are gat, Wsa and des in the second.
When Ducky is reading Michael's letter in the lab out loud when Gibbs comes in, the papers side changes in different shots.
In the first scene the fire truck bears a Virginia Local Government license plate with the wrong color scheme. Instead of the normal dark blue on white, local government plates are dark blue on a tan background.
At 26:07, when Tim is in the morgue looking at the dead body, Ducky walks in and asks "Looking for something Tony?" This is incorrect. Ducky says Timothy, not Tony.
When Tony is in Tim's apartment watching how Tim writes his novels, it shows Tim typing on a pre-50s/pre-40s manual typewriter. Tim comes to the realization that because he types on it, rather than a computer, that's how the murder would know the unfolding plot of the novel he's working on, and copy the murders. When they show up at the NCIS offices, he's holding up a film ribbon on which you can see each character. Film ribbons didn't begin showing up on typewriters until the 1960s, and only on electric typewriters. As seen on the sample that Tony & Tim typed up, Tim's typewriter used a cloth ribbon, from which you cannot read anything that anyone's typed with it.