The Dark Age - S2-E8
Revealing mistake: When Buffy and Giles are talking in the school in the final scene, the same extra (in a beige shirt and blue jeans) walks out of the room behind Buffy twice. (00:42:50)
The Dark Age - S2-E8
Continuity mistake: When Giles is making calls in his apartment, he takes his glasses off and drops them on the desk, just above the notebook with his list of names. But in the close up of the notebook, the glasses are now on the top of the notebook.
The Dark Age - S2-E8
Continuity mistake: Cordelia tells the Scoobies that Giles was talking to the police about a homicide, but this wasn't mentioned in the time that she was in the room. (00:18:15)
The Dark Age - S2-E8
Continuity mistake: At the end of the episode, Buffy complains to Willow and Xander that she will have to blow her allowance on getting the tattoo removed before her Mom sees it. Moments later when Buffy is talking to Giles, the tattoo is gone. (00:40:45 - 00:42:30)
Chosen answer: He had larangitis and because of the shooting specifications they had to have him shoot the scene with a bad throat, they then re-recorded his lines and dubbed them. At various points during the scene and indeed the episode you can see him touch his throat or rub it.