What behaviour is expected:

If there is no recipe for the items in the crafting grid, taking items out of the result slot of the crafting inventory should leave the items in the crafting grid alone.

What behaviour is observed:

After taking an item out of the result slot, the items in the crafting grid are first decremented by one and then doubled.
https://i.imgur.com/vZUlwIN.png
https://i.imgur.com/k0hneCD.png

Steps/models to reproduce:

Put a stack of 2-64 items into a crafting table
Set the result slot using either .setResult() or .setItem()
Take the item of the result slot while leaving the crafting grid alone

Plugin list:

Only the plugin I'm using to test this

Paper build number:

504