The Spirit Realm

did it show up in short buff box? if so those disappear on zone so that may have been issue.

Technically, Auras do fade, only they reappear before you've finished loading. See, the way Auras work is you summon an invisible non-attack/attackable* pet (sorta like the wizard familiar) which recasts the Aura in an AE effect around themselves every tick. This is why, when going selos-speed, the Aura fades from you at times - you're outrunning the AE effect between each tick as the pet struggles to keep up.

* = One should note that there's a bug which makes your aura-pet start hitting you. I've not figured out how, but they're pretty annoying (invisible npc that keeps hitting you for 1,2,2,1,1,1) until you figure out it's the aura and you can depop it