Over this last week, I have attempted to do the event “Rescue the Villagers and Defeat the Harpy Kidnappers” in the area of Tanglerot Hills. Both times, there is a single villager left that you cannot interact with in any way. He never dies, he just stands there. As a result, the harpies spawn endlessly, and you can never complete the event.
It also seems to adversely affect the skill challenge in the area. Even though I had not completed it, it told me that I had already done it. Eventually, it allowed me to complete it once someone else triggered it. Not sure if it’s related to the bugged event or not.