[GAMEPLAY] Can't directly purchase Biscuits of Rejuvenation

With the Biscuit mastery equipped, if you purchase Health Potions, they transform into Biscuits of Rejuvenation. However, if you click on the Biscuits in your inventory (in the bottom left of the store window), it brings up the store page for Biscuits of Rejuvenation, but you're unable to purchase them, despite having enough gold and the mastery equipped. The only way to purchase the Biscuits is to go through the Health Potions store page.