In the Warrior quest, Beat Bartleby, once Bartleby is defeated, he is supposed to stop attacking and offer question completion after his health is reduced to a certain point.
However, in MangosOne, Bartleby continues to assault the player after the threshold for harming has completed (player stops attacking & quest is marked complete), and despite the quest being considered 'complete', even if the player manages to run away and return to Bartleby, he does not offer quest completion.
This locks the warrior learning defensive stance behind a bug.
EDIT: See comment below. There's a "workaround."