Confirming this bug. I have \aITEM 471907499 1288378810 0 0 0:[Quickened Shrunken Goblin Skull Earring]\/a I equipped the earring, then used it Checked my spells , and Grim Aura was visible. Zoned to Coliseum of Valor from my guild hall Grim Aura is no longer in my spells. I was able to reequip the earring and re-cast Grim Aura, so there is a workaround (just wait until you are in-zone to use)