Dr. Noxious disappeared?

[Tamino]

I started a new alt a few days ago. I was making all sewer quests and bang! In Fetid Halls Dr. Noxious and its minions are missing. Enemies count is 24, that are the enemies defending containment units; killing them all terminates the level and still no trace of evil doctor. Did something go wrong with the latest update?

[bronislav84]

He was already killed. You entered an instance where somebody already killed the boss and left. When in doubt, exit through the door then come back in. Makes a new Halls instance for you. This works for any of the quest instances.

If you entered from a hosted instance you had previously done already and never entered Halls then I dunno.