Yeena's store not expanding after completing "Intruders in Black"

After completing "Intruders in Black" and getting quest rewards from Greust, another set of gems should become available for purchase from Yeena, which aren't. Herald of Purity being one of them, which I need for the Witch build I'm working on. I've tried completing more quests in act 2, to the point of finishing the act. I've tried traveling to Lioneye's Watch and back, and have logged out and back in multiple times in an effort to fix this issue. I've even tried logging in with a different character to see if I can purchase the requisite gem, and it's not available with that character either.

Does she not sell any of the Purity gems? Is she selling skill gems, or only support gems?

Even if you're unable to solve your issue here, the gem would be available for purchase from Siosa in Act 3.