Orc Mastery Quest questionFollow

I received the Orc Mastery Quest after inspecting the shield at level 11.

I then went to kill ghostly orcs in Siege Lands. After about 50 kills, I figured that I should have at least 1 drop. I went to inspect my quest journal, and the quest had disappeared.

I searched under completed quests too. I petitioned and talked to a GM. He said that I should ask my fellow players for help - (hinting that I was missing something). I told him that I already received the quest, but he would say nothing more.

No one could tell me a thing. I was thinking that perhaps it was my level. I went back to the shield at level 12 and 13. I still can't get the quest.

Any suggestions? Am I missing something?

Thank you.

Sad but true , you won't get credit for killing orcs and undead in the same mob :P