I got this after I got the last "First Emblem of [Giant]" achievement from an assortment of Street Projects and interacting with Shrines after reaching 1000 Favor.
Maybe trading, receiving, and picking up dropped emblems don't trigger the achievement requirements?
I have some idea why I didn't get Super-Sized Sycophant. I think it's because my emblem of Mab is not registering for some reason, and I don't have the "First Emblem of Mab" achievement.
Thing is, I have the Mab emblem although I don't remember exactly how I got it. :(