The problem may not be in some servers, but in mine, and a few others they may have this problem.
In Undercity one of the seats is missing, and you can't get the sharing buff unless you get all of the 5 foods.
(Cranberry is missing for mine)
To fix this problem
Simply go to "Brill", and theres 4-5 tables there where you can eat. Eat at the seat thats missing in uc 5 times, and head back to uc and eat the rest, you will get the completion.
IDK why its all glitched, but if you want to finish it fast before blizz fixes it, this is the way to do it.[/COLOR]