Example: Helmets of all types, iron to diamond, have the same enchantment such as unbreaking. All swords from wood to diamond have the same enchantment such as fire aspect. The list goes on with the common occasion of every item having the same exact enchanting. i have tried enchanting a couple items to fix the bug, but it does not seem to work. Sometimes an enchantment will be a different level such as protection 3 instead of 4.

Quick update: There is a slight chance of items being different enchantments but for the majority of the time the enchantments are either very similar or the exact same.