Way to remove curse of vanishing with grindstone

I have noticed that the curse of vanishing, at least on fishing rods (only tool I have tested with) can be removed on a grindstone, but only if the cursed fishing rod is put in the bottom slot and another fishing rod (without the curse) is in the top slot. Effectively, if a curse only exists on the bottom tool when merging 2 in the grindstone, it seems to vanish.