Of course, this could just be an Armory bug, so I did my level best to check it out for myself, by logging on to Proudmoore, the only server yet to have reached phase four. However, I learned that although Shaani spawns when phase four is activated, she doesn't sell gems until the Alchemy Lab is completed, much like Smith Hauthaa and the Anvil. So I can't confirm this with anything more than the Armory data at the moment. Proudmooreans, get going on Discovering your Roots, so we can uncover the truth of this gem-price-drop rumor.
If it's true, Badges of Justice might be worth more gold than we thought, depending on what the price of these epic gems stabilizes at.