See https://www.wowhead.com/npc=162819/warbringer-malkorak

I believe this was already reported/discussed somewhere, but I can't find it right now. As far as I understand, the tracking for this item is off because there are two NPCs and they don't always drop loot? Not sure if there's anything to be done about it, though.

It's possible things have changed since tracking for it was first added, so perhaps revisiting the issue would lead to a fix now?