I fight the cultists in the house near the goblins. Astarion first backstabbed the female merchant with one hit, so no fight started. Then I used backstab against the dwarf outside. It did not kill him so Astarion started combat with 3. Astarion killed the dwarf with the next attack and Trynn went outside and cast hunters mark on Astarion. ( big red circle over him ). Astarion managed to hide and sneaked away from the house. When I was far away from the house combat ended. The two inside the house are friendly again and Astarion has permanently hunters mark.
Not sure if this counts as bug, but it feels wrong somehow.
UPDATE: I have found out that you can cheat this fight without problems: Attack a friendly character with sneak attack from stealth while standing close to the door to the basement. They become hostile but they are surprized (cannot make attack of opportunety) Attack again and use the door to the basement. You are out of combat and when you come back out of the basement they are friendly again, but they keep their reduced HP from your attacks. This way you can kill them with no risk at all.
Hunters mark disappeared on Astarion when I killed Trynn.
Prof. Dr. Dr. Mad S. Tist
World leading expert of artificial stupidity. Because there are too many people who work on artificial intelligence already