This started happening to me as well as of hotfix#21. I don't understand why it happens as it is totally random. Has occured during camp, Astarion attacks then when I kill him I have to also kill anyone not currently in the party and leads to every other NPC in the game to turn hostile on sight. A new game is required as I can't find any way to pinpoint what the problem is and veryfying integrity of the files does nothing.
