Out Of Mind, Out Of Sight - S1-E11
Continuity mistake: In the beginning of the episode, when Cordelia's date is in the locker room and he talks to two other students, pay attention. There's a combination lock and a baseball bat on top of the lockers. They change positions repeatedly between cuts, getting closer and further apart almost at random depending on the shot.
Out Of Mind, Out Of Sight - S1-E11
Continuity mistake: When the school-bell rings at the beginning of the episode after Cordelia talks about hitting the girl on the bike, in the first shot Willow is just starting to put her book into her backpack and is still seated. In the next shot, Willow is suddenly starting to stand up and has already put her book away.
Out Of Mind, Out Of Sight - S1-E11
Continuity mistake: When Cordelia is talking about hitting the girl on a bike with her car and the bell rings, pay attention to Willow's hands. As it cuts from the front angle to the back angle, Willow's hands instantly change positions. (In the first shot, her hands are together, but in the next, her arms are crossed in different directions).
Out Of Mind, Out Of Sight - S1-E11
Continuity mistake: When Cordelia raises her hand in the class at the beginning of the episode, look at Harmony's hand on the desk next to her. Harmony's hand instantly changes position and moves about six inches to her left between cuts when Cordelia is called on.
Out Of Mind, Out Of Sight - S1-E11
Continuity mistake: This is subtle and hard to notice. When the teacher is giving a lecture in the beginning, she says "Ok, so talk to me people " and starts to turn and walk to her right. When the camera cuts, she starts to turn and walk to her right a second time. It goes by fast, so it's kinda hard to see.
Out Of Mind, Out Of Sight - S1-E11
Visible crew/equipment: When Buffy and Cordelia enter the mop closet you can see the shadow of the boom microphone on the wall near Buffy's head (left side of screen). (00:31:44)
Out Of Mind, Out Of Sight - S1-E11
Continuity mistake: When Cordelia is giving her May Queen speech, Willow notices 2 body guards standing around. In both shots you can see the same 2 girls, wearing light blue and grey, walk behind The Body guards. The same girl in light blue can also be seen in several different shots, in the crowd listening to Cordelia and walking around as Buffy talks to Willow and Xander.
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.