Had one bow with multiple enchantments on it in my personal inventory and was going to enchant another bow as well. I didn't like the preview enchantment so I was going to enchant a book instead to clear the table. Canceled out of the Enchant UI and it dropped the bow I decided against enchanting. After I picked it up I realized my Bow with multiple enchantments was just a regular bow all of the sudden. This also happened with a pick axe.