Game Mechanics: Message spam while having auto attack on during Divine Aura

[Nimblerot]

So just now, while my group was getting raped by the undead king in BB, I had to DA. I had auto attack on when I cast it, and once it was on, my chat box was spammed by "You can't attack while vulnerable!". We're talking like 20 lines of it a second spam.

It goes away when you turn off auto attack, but happens when you turn it back on. Kinda obnoxious, thought i'd report it.