Perennials: Platycodon Perlmutter Double Flower?!, 2 by Pfg

Pfg wrote:
I've just grown these from seed (bought last fall from Diane's seeds), and some are beginning to bloom. What to my great surprise this gorgeous double flower appeared! I can't find any reference to double blooms on this cultivar anywhere. Does anyone here know anything about it? Is this known to happen occasionally, or should I keep this plant separate from the others and see if the seeds come true?

Thanks!

Pam