[GAMEPLAY] Unknown, blank buff appears on buff bar after taking Blue Golem that is not Crest of AG

While I was attempting to recreate a bug in a custom game, a blank, blue icon appeared on the buff bar immediately after I took down the Blue Golem. However, as noted in the title, this buff was not the Blue Buff, Crest of the Ancient Golem. It was a different buff. I have no idea what this is, as all the buffs that I should have, such as Strength of the Ages, were already on the buff bar and visible.

This unidentified buff is shown in the attached photo. http://i.imgur.com/ua2aDbM.png