Different peppers, from the same saved seed pod

I seem to have an oddity growing. I saved Cayenne Pepper seeds, in whole pods. I cracked a pod open, and planted only those seeds in a pot.

Well, come to maturity – two of the plants are growing different peppers, while 5 of them are growing the normal Cayennes.

How?

1st image is how they've grown for the last 5 years, 2nd image is my oddity!