Revealing mistake: When Ziva is hugging her dead father, you can see him breathing. (00:36:00)
Continuity mistake: Abby says that McGee is the most helpful person with clipboards. When she does, the position of the clipboard in her arms is constantly changing between instant cuts. (00:03:30)
Continuity mistake: When we first see young Abby, the way she's holding her bear changes between shots. (00:04:50)
Continuity mistake: In the evidence locker, Ziva opens a folder and the white notepad is on the left-hand side. Camera changes to behind her, and now the white pad is on the right. (00:26:40)
Factual error: There is a flashback scene in this episode, where a young, dejected Abby Sciuto is walking along railroad tracks after failing to give the bear back to Ricki. This scene starts with a shot of the railroad tracks, then pans up to Abby. It can be seen that the rails are laid on concrete sleepers, with modern steel clips holding the rails to the sleepers. Given that the flashback appears to take place when she was at least a couple of decades younger (i.e. the mid-1990s), such modern methods of construction wouldn't have been used. A period-accurate railroad track would have wooden sleepers, spikes and lighter rail. As such, it's obvious that the producers just went to the nearest railroad tracks and filmed the scene there.
Continuity mistake: We see a close-up of Kevin's poster that Ziva is holding. In the close-up, she is holding the poster on the right-hand side. When the shot changes to a wider shot showing Ziva and Tony, Ziva is no longer holding the poster on the right-hand side, but is now holding it on the bottom. (00:04:40)
Visible crew/equipment: While at Gitmo, Sergeant Spooner is attacked by a detainee, and when Tony joins in the tussle the gun is fired. It then cuts to the tented Global Courier van, and the pink tape mark is visible on the ground behind the van. (00:35:50)
Character mistake: Ducky states that the Romans believed that the vein of 4th finger on the left hand ran directly to the heart, thus, logically, it was the "ring" finger. However, there is no evidence that the belief originated with the Romans, nor that the 4th finger has a special vein...the fingers in the hand have a similar vein structure.
Anonymous Was a Woman - S11-E4
Continuity mistake: In the scene when Tony and Gibbs are riding together and Tony is eating a sandwich, it starts about half gone, the angle changes and there is only a bite gone, the angle changes again and it is about half gone again.
Visible crew/equipment: While Gibbs is with Abby in the lab when she mentions her dissection of the laptop, in the overhead shot as Abby says, "since it came in here, Gibbs," the moving wheel of the camera dolly is visible at the bottom, right corner of the screen. (00:09:35)
Continuity mistake: When Tony is sitting at McGee's desk talking to Delilah, Tony's holding the phone to his left ear with his left hand, but in the overhead shot Tony's holding the phone to his right ear with his right hand. (00:15:50)
Kill Chain - S11-E12
Character mistake: Ellie Bishop introduces herself to Delilah as Emily Bishop in the elevator scene. Her name's Eleanor in the series, but the actress' real name is Emily. She used her real first name in the scene.
Suggested correction: Ellie correctly says, "I'm Ellie Bishop," when she introduces herself to Delilah. I slowed the speed down to 0.5x to confirm.
Crescent City: Part 1 - S11-E18
Visible crew/equipment: When Gibbs asks about the crime scene where Doyle was killed, just as LaSalle, Brody, and Gibbs head out the door, the white T-mark taped to the rug is visible near the door. (00:36:35)