DUPLICATION and UNLIMITED XP

so i went to disenchant my diamond   sword and it keeps giving me  diamond sowrds and exp at first i thought it was a bug i tried it with other things  but it only works with weapons AND tools that are enchanted  and it lets you keep the enchanted weapon and give you a lot of non enchanted weapons.  i looked it up and found this as well please patch. https://www.youtube.com/watch?v=LxSCGUpxsPs