I would guess you need to do the alliance equivalent quest that gets you eye of the beast. General Draks Demise. And if you already did it you can’t do it for the buff. Just like rend when you turn it in it does the buff. But they didn’t do it on purpose so it didn’t add some quest for everyone to do. Just a guess though.
Guess not they did add a new quest. New guess, you have to go pick that up from the keep before hand.