Factual error: When Tim is tracing the British agent's mobile phone it shows that the number traced is a British land line number (01632) not a mobile number (starting 07...). The number is also seven digits long, not six as is the format in the UK.
Continuity mistake: Episode 8x21, "Dead Reflection": When Tony and Ziva are staking out PO Donner's house, Tony's grip on the hot dog in his hand changes between shots. (00:11:40)
Plot hole: For such a dangerous serial killer, Lt. Cobb should be more securely restrained than he is. He wears a simple pair of handcuffs, with only one security escort.
Other mistake: When EJ gets spooked near the end and turns to face a wall with a doorway to "North Stairway C", she faces the camera with her torch facing the camera directly. However behind her is a perfect shadow on The Wall of herself. This shouldn't be possible as the only source of light, as shown, is from her torch. Cade and Levin are in a different room so couldn't be their torches. (00:39:20)
Visible crew/equipment: After Tony says the line "What would Steve McQueen do?" we get an extreme closeup of the front bumper of a car with Virginia plates on it. Just to the screen right of the plate, you can see the reflection of some of the filming rig used for the shot. (00:31:50)
Out of the Frying Pan - S8-E18
Continuity mistake: The way the axe faces when Leon leans it against The Wall changes between shots. Sometimes it's facing left, others it's facing right. (00:28:00)
Visible crew/equipment: When Gibbs finds out that Otto has been found dead, he looks at Leona. In Leona's glasses you can see the reflection of the filming crew. (00:30:50)
Continuity mistake: When The DA comes into NCIS after confronting Gibbs at his house, Ziva's action's in the background are constantly changing between cuts. (00:23:40)
Continuity mistake: When Ziva is photographing the bedroom she has the camera raised to her eye in one shot and lowered in the next when the DA asks about DiNozzo. (00:05:40)
Continuity mistake: Ziva is photographing the scene and takes a picture of the empty DVD player with a yellow evidence marker number 5 on top of it, Gibbs is then seen with the same marker in his hand before placing it on the DVD player. (00:04:40)
Continuity mistake: At the start, the disk falls out the paper and the case is touching the door mat. When the shot changes to a close up of the case being picked up, the case is no longer touching the mat. (00:01:05)
Broken Arrow - S8-E7
Continuity mistake: The position of the mobile phone on the victim changes from when we see the Admiral discovering the body and NCIS taking the photos. (00:02:40)
Chosen answer: It is never stated, however she must have been there several years if she is on presidential detail.