Problem resetting dungeon?

[void.pointer]

I'm on "Chapter 20: Abandoned Post" where I have to go into the ad-hoc instance where Adder's Nest is to obtain Dumbak's Bag. I skipped over the escort piece (after you let him out of the cage) by accident and killed the brothers & final boss at the end. I went back and escorted him, and it's asking me to recover Dumbak's Bag, but the boss isn't there anymore. I left the dungeon and re-entered and it hasn't reset.

 

How do I reset the dungeon? How can I complete this quest?

[void.pointer]

Never mind, apparently the boss at the end will respawn when you leave but not the rest of the mobs in the dungeon. It tricked me because I didn't see the earlier mobs come back.