Visible crew/equipment: In the scene at Buffy's house, her mum comes into her room and says "Buffy, I'm home". As she says this a boom mic is visible above her head.
Visible crew/equipment: In the scene where Buffy is packing Joyce's clothes into a suitcase you can see a mic moving at the top of the shot as they walk through the door.
Visible crew/equipment: When Buffy is going through the murdered Professor's office, Angel seems to trip through the doorway. To the top right above Angel's head a boom mike is visible twice.
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.