When using an enchantment such as Impaling V or Smite V, the "Overkill" achievement does not register, despite dealing more than 9 hearts of damage in a single hit. Using an Impaling V trident, which deals 10.25 hearts of damage, the achievement did not register. A similar issue occurred with using Smite, even when the enchantments should be working, such as when I did a critical attack on a Drowned that was in water, killing it in one hit.