After right clicking and equipping the outfit, I immediately changed back to the original outfit I was wearing by going into the wardrobe section of the hero panel (I may or may not have had the hero panel open when I right clicked the Harbinger outfit previously). I noticed that the icon for the Harbinger outfit was not present, so I could not switch back to it if I wanted to. I went into the gem store and found that I had indeed unlocked it as evidence by the tooltip in the recently purchased list. I closed the Hero panel and reopened it and only then was the icon there for me to switch to it. Not a huge issue but it did freak me out at first considering it was worth quite a few gems.