After beating the goblins and saving the grove I went down to the beach with the singing. The journal updated that I found a child in trance. I returned to the grove without speaking to the child and then I chose to end the day. When I arrive in the camp at night the journal updates and pretends that I talked with the child and saved it from the harpies. I did NOT talk with the child and I did NOT meet any harpies so far.
Update: I returned to the beach after resting. I get 15EXP when I get to the area even though I have been here before. The child is gone, there are hapies around and when I enter the area the log updates and says the quest is finished.
Prof. Dr. Dr. Mad S. Tist
World leading expert of artificial stupidity. Because there are too many people who work on artificial intelligence already