Polymock Quest Progression

I have just beaten Grulhammer Silverfist and Necromancer Volumandus in Polymock (along with all of the people prior to them).

According to GW Wiki, I should fight Dune Teardrinker and then fight Master Hoff. However, Master Hoff will not give me the quest to fight Dune Teardrinker.

Is there something (like completing a quest, or grinding more Asura faction) that I have to do before Hoff will give me the next quest? Thanks in advance.