I’ve been having problems with quests breaking on me but this takes the cake. I was doing the “The Blackwood corrupted” quest and it just broke. So I filled the bowl, then I went to the camps and got all the berries, nuts, and grains. Killed some of them then cleansed them, they all became good. Killed the boss, but even then it still said I didn’t do it and I needed to get berries and grains. They all turn evil again and killed me. Quest failed.
After you kill the boss, there is a container that spawns. You need to loot the container, it contains his “totem?” that you need to complete the quest.
Yes they do turn back to hostile after a very short time, and respawn quickly. You have to be fast with the looting the crate and getting the heck out of the camp.