Lost Mail in Dalaran

Quest: Lost Mail
Quest NPC: Madam Goya
Quest Location: Legion Dalaran Underbelly
Problem: Cannot turn in the quest. The quest turn in icon does not appear at Madame Goya. It shows in the Portal Area for Horde Section on the main level of Legion Dalaran.

I have save problem with my lv.20 character.
then i switch lv.80 character can turn in this quest.
I think this is related to the minimum level of interaction in the black market.
And I am certain that this is a recent bug, as I have previously completed tasks using the role of lv.20