All you need is a SOLIDWORKS ID, or a new or existing 3DEXPERIENCE ID.
SW2020 REV4. I created 2 parts and placed them into an assembly and fully mate them together. Each part has a hole and one hole is located fully. I mate the unlocated hole position to the defined hole and the mate is not fully defined (blue star not black). The holes are over top of each other as if they are fully defined but the one hole can be dragged away after mating.SolidworksModeling And Assemblie