Legendary quest Rune of Shadowbinding giving no credit

[Mienerva-kazzak]

To The test : rune of shadow.... BUGGED!(LEGGO QUEST)

cmon blizzard this legendary quest is bugged i used rune on all 3 bosses of all 3 difficluties and yet none of them work i already spent too much gold and time for this non sense quest fixxx ittt asaaaap!!!