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.