Duplication glitch with anvil

There's a glitch with the anvil where you can duplicate stacks of items. Say you have a stack of 20 diamonds. You put it in the anvil and add a space after Diamond in the rename field. This will make it show up in the output box as 20 diamond. You can take out 19 diamond from the output box and then you can also take out the 20 in the input box. This leaves you with 39 diamonds. Tested on 1.5.1 on Windows 10 and Switch. Works on both.