If both sides of the PCB pin and both sides of the connector are connected then I guess that would constitute a tiny loop, but would it matter in a well-shielded rack? I don't know enough to say. It's a good question.
If you're designing a board that will only ever be used in one rack, then you can design accordingly. For what it's worth, I see that API and CAPI only plate the solder-side of the edge connector - whereas RND and SSL seem to plate both sides.