Since the GU106 patch the Tinkered crafting tools (eg. Gnomish Ring Press) are no longer equip optional. They show the benefit when equipped but not when unequipped.
You should be able to drag it into a slot - the equip on right-click was removed quite some time ago on many items.
Lots of weirdness like that has been happening to old crafting rewards for quite a while. I think they removed the equip optional to force us to chose between items that used to stack when kept in your inventory.
My poor tailor still clutches her Sewing Needle as appearance even though they capriciously removed crafting stats on old items long ago. In my experience her, craft stuff that gets borked takes years to fix, if they ever do.