Mind Flay: Insanity does no damage to certain classes in Ashran. Instead of a normal 2 second cast, the spell cast almost instantly and does literally zero damage.
Classes that it doesn’t seem to ever work against: Warrior, Death Knight, Paladin
Classes that it works normally against: Hunter, Priest, Druid, Warlock
I haven’t noticed the problem anywhere except Ashran yet but I will keep looking.