So having just read up... It seems Nicholas Brendon has pretty severe depression, alcoholism and prescription medication addiction and has been arrested several times for smashing up hotel rooms, has been arrested following an incident at a Comic Con, missed another one he was meant to be at because he was arrested for something else, and has also been arrested multiple times for physically assaulting his girlfriend and once for physically assaulting another woman. Not metoo type stuff, just straight-up physical violence like punching / strangling
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Honestly it all kind of trashes the memory of the show a bit, which is sad.