Other mistake: It is said G. Callen has lived in 37 foster homes between the ages 5 and 18, the longest ever having stayed in one is 3 months. 5-18 is 13 years, meaning even if he had lived 3 months in EVERY foster home, it'd have to be a minimum of 52 foster homes. Since 3 months was the longest, it is logical that the others were shorter therefore the number would have had to be much higher.
Continuity mistake: When Sam finds the list of "Guitar Hero" receipts in Corporal Valdivia's house, he flips the top page to the bottom of the pile, and in the next shot he has the following page in his hand, without having moved. (00:06:25)
Other mistake: Hetty's image appears in a mirror talking to Kensey who is getting changed for an undercover assignment when Kensey walks out of the changing area the mirror is on her right but Hetty is in front of Kensey and could not have appeared in the mirror.
Continuity mistake: At the beginning a person is shot in the back of the head during a surveillance. The camera is filming a man and a woman on a boat at a marina. The feed is being played in real-time on the laptop. The killer starts to gather all the recording equipment, including dismounting the camera off the stand. The killer called the man on the boat to say "it's done". The computer screen shows the man on the boat leaving the boat even after the camera was dismounted.
Revealing mistake: Callan chases bad guy Ethan through the yard. Ethan runs down a set of stairs and towards the camera, before hiding between tanks. While running, Ethan's face is fully visible and it is very clear that it is not actor Charles Esten.
Revealing mistake: The dead victim is being examined in the morgue, right as the mortician says "the kid put up a fight" the dead victim swallows as she strokes his hair and says the word "fight." (00:09:35)
Continuity mistake: In the car chase at the beginning of the episode, Earl Mayfield's pick up smashes into the SUV driven by Conrad Weaver. Part of the bumper comes adrift and is seen hanging low. When Weaver's SUV flips over, Mayfield turns around and drives back up to him. As he approaches the bumper has reattached itself. (00:01:00)
Continuity mistake: Sam and Hetty are talking at her desk. There are two cups of tea on the desk. The ear of one of the cups is on the left in one shot, then on the right on the next.
Factual error: When the stolen freight train is braking, the air pipe becomes disconnected. This should trigger the brakes on the train, but the train keeps going with no brakes. When the train is being slowed with no brakes working, why are there sparks coming from all wheels on the train? (00:32:00 - 00:38:00)
Continuity mistake: When Deeks is shot in 2-17 "Personal", his records show no next of kin. However in later episodes he has a mother.
Continuity mistake: After the drive-by shooting at the Federal Building, when Owen and Sam escort the defector and his girlfriend into the sedan, the license plate number is "5GOI417" which soon changes to "5PCI294" when Sam drives backwards. Then it changes back to "5GOI417" when Owen and Sam leave the car, and yet it's "5PCI294" again when Owen points his gun at the camera.
Visible crew/equipment: In the rec hall, when Kensi feigns sickness while posing as a cadet the gunman jumps off the stage, and as Kensi bends over the small rectangular bulge of her mic pack can be seen at her back. (00:30:25)
