Playing Aggro Mage, got Potion belt from Prismatic Elemental, chose two concoctions if Hazy connection and Bubbling Concoction, only Hazy Concoction showed up, Bubbling simply did not combine or appear in my hand.
Was there room in your hand for both concoctions?
it happened to me several times that with potion belt the second potion is not crafted giving me only the first of 2