Infinite XP / Grindstone Glitch

After manually crafting an item, like a cake in the crafting table, it can disappear, then you can go to the grindstone, put a single enchanted item in and disenchant the same item over and over  until your inventory is full.   Then you drop it all, pick up the enchanted item, and repeat.

The method above is the one I used to confirm>

Apparently similar may be accomplished by using a book and quill, filling out some content, signing it with title/author.    Then it may be a normal book again.  Then you go back into the book and it may become enchanted.   Then the grindstone glitch works.

The original video I found this on is here.
https://www.reddit.com/r/Minecraft/comments/g1eoi7/infinite_xpduplication_grindstone_bug_version/#bottom-comments

As mentioned I was able to replicate the cake method.