Mod version

1.20-8

A description of the issue

While renaming a treasure enchanted book, like Swift Sneak, Soul Speed or Mending, the enchanted book gains a new enchant.

Log or crash report

No response

This is only possible when giving illegal enchantments with commands via nbt, or by config editing to allow and then disallow after obtaining. Either way, discussed on the Rattiest Gang discord that it's not worth fixing since it's so circumstantial

It does not add a new enchant to enchantments like Efficiency, Molten, Accumulate, Double Dash, etc. since they are not treasure enchantments.