Before storming into the bug section I need to ask, has anyone ever played this and found the tavern section empty? The first time I played the game there was no one there, so in spite of finishing the area and getting notifications regarding the quest, I never got the achievement. I assumed I'd missed some hard to spot guy, but doing it the second time, there's a tavern full of blue ringed characters.

I've only been there on two playthroughs, but nope. Well, other than being empty after sorting out a disagreement, of course.

It's possible to complete the quest without going to the tavern at all, I haven't done this but maybe it clears out under certain quest resolution conditions?