Originally Posted by FBinNY

OK, so this is a no problem "problem". The bottom of the race or cone is not flat intentionally for the same reason that cups and saucers are footed, namely to oprimize level seating on uneven surfaces.

In this case the crown's seat is the flat zone near the center, and the bevel is to provide clearance in the event that the seating area isn't perfectly flat. On most forks you wouldn't have noticed, because the seat area is relative small and the fork slopes away from it.

However, your fork has the wide flat disk which makes it look wrong, when it actually isn't.

If it bothers you, fill the gap with some kind of caulking.

BTW - it's also possible that the disk is actually part of the original headset that you forgot to remove. It's a possibility I'd explore by setting a punch against it and seeing if it moves up with gentle prodding.