My guess is that they are getting to much light. My Sunpatiens will get white spots when they are stress out by being in sun and little water. Maybe you have a white one that got in the mix or if they were the Star variety sometimes these will revert to white and back to orange. This variety has a white strip that runs between the center of each petal creating a star pattern.

Mine are doing the same thing, and I have red, orange, coral and red. They are doing it in pots and in the beds of 3 separate residences I garden. I am going to try to water early in the morning and make sure they aren't burning due to being wet. I use miracle grow but I don't think it is the fertilizer or soil because they are doing it several flats that haven't been planted yet. I am assuming they are stressed from too much heat as well. They did not do it last year in the same heat, but the temperature spiked here in Oklahoma very rapidly after being cool and very wet.

Same here. I just thought it was a hybrid. Sun makes perfect sense.