Hungry Scientist

I am a big fan of Skor bars. I bought one at a gas station the other day and found that instead of that nice chocolate brown color it had turned completely white. I grabbed another bar from the same box, unwrapped it, and found the color you would expect—a nice chocolate brown. Considering that the two bars came from the same box, one would expect them to be the same age, and likely from the same batch. So my question is, what causes this effect? Maybe it was oxidation from a bad wrapper that let air sneak in?