If they are white, and otherwise normal, then they just got pollinated by some other corn (or it is just within the genetics of the that popcorn variety). Either way, nothing to worry about.
But they don't look normal...? They look to me like they are infected with a fungus. Maybe corn smut? Not a problem, though, just don't eat those parts. And then the ones that are white and look normal would be fungal infected also, just at an earlier stage of development. Don't eat those, either.
