See No Evil - S2-E1
Revealing mistake: When the team speed into the lot at the end, tyre marks are visible on the ground from previous takes. (00:34:40)
See No Evil - S2-E1
Revealing mistake: Just as Gibbs and Tony head to Mtec, we see a close up of the webcam on the General's computer. Note the brand name. It's been flipped. (00:16:40)
See No Evil - S2-E1
Continuity mistake: When Gibbs leads Tony and Kate to MTAC, Tony extends his arm in a "ladies first" gesture to let Kate go ahead of him, then drops his arm to his side. In the next shot, his arm is extended again and he drops it a second time. (00:16:30)
Bikini Wax - S2-E18
Continuity mistake: When Gibbs shows his identification to Jonathan Redding's supervisor, he holds the badge from the top of the wallet, then at the bottom, then back at the top. (00:26:40)
Continuity mistake: When Gibbs thumps Tony on the back at the storage locker, his hand is balled up in a fist. In the next shot, Gibbs' hand is extended flat. The pen in Gibbs' hand also disappears. (00:04:45)
See No Evil - S2-E1
Continuity mistake: In the scene where Gibbs' phone breaks, and he tells McGee to "reboot" it, Tony is in the back, getting a phone out of the cabinet. He starts to give the phone to McGee. The next shot, the cabinet opens again, and Tony pulls out the phone again and gives it to McGee. (00:04:55)
Lt. Jane Doe - S2-E4
Plot hole: It really doesn't make sense that they found the real killer from Jane Doe #1 assuming he also killed Jane Doe #2. They only found him because they assumed he was in prison for the last 10 years. One could explain that he must have gone to prison shortly after the first murder because he said he'd be back but wasn't, but that he was actually recently released is just pure coincidence. And without finding him they would never have suspected Officer Cluxton.
Continuity mistake: Gibbs puts his gun in his drawer on a blue folder then goes to talk to Fornell in the lift. When he comes back, he picks his gun up and the contents of the drawer and position of the gun have completely changed. (00:14:50 - 00:16:50)
Other mistake: It's the same license plate (107TIX) on Runyon's truck when the video footage is enhanced by Abby as the Ford sedan in S2 E10 "Chained" when Dinnozo and Jeffery leave the cabin.
Audio problem: When Moore's widow sees her lover being brought in, she shouts "Roger!" - but her lips don't move. (00:33:05)
Factual error: Obviously written to make the story interesting, but Gibbs says that the first criminal caught by DNA was a Mafia don in Sicily. Well as anyone interested in forensics knows it was Colin Pitchfork in England.
Chosen answer: It is never stated, however she must have been there several years if she is on presidential detail.