I have completed the “open 40 trick or treat bags” achievement 100% and it did not result in Emissary of the Mad King updating or indicating progress. I spoke in map chat and found that it has updated for others who have completed this, but they also spoke of issues wherein it did not update after finishing Master Carver and the like.
If Emissary of the Mad King is bugged, I think it should be a priority fix since it is a pertinent and pressing issue. I for one will be wholely chapped if I miss out on the awesome title because of a bug.
