Perhaps not surprising, but I am experiencing a similar issue.
Brand-new Technics SL-1300G installed as per instructions (followed meticulously). I ensured the screws, washers etc were installed 100% correctly. Only to find a ~1mm spacing variance on the platter itself. The platter is placed perfectly level.
Now it might sound negligible, but when the platter spins, it actually causes a vertical displacement, causing the record to move up and down on the platter itself. Perhaps it doesn't cause any audible effect (who knows?), but nonetheless highly disappointed.

