I can't buy several weapon essences from the Lectern of Enchantment due to "you can hold only one at a time" but I don't have any in my inventory. I imagine these essences that I "have in my inventory" are for when I abandoned them in the past because I didn't want them in my inventory and I remember being able to pick them back up at the Lectern, but I don't see them anymore. Which currently makes it impossible for me to get these weapons.