I'm not a plant expert by any stretch but I have seen and been involved in a few conversations about this issue. Here is what I know.
Some believe what we are calling light bleaching is actually a type of albinism that modern high power leds unlock somehow. This bleaching was common in his, etc and was really bleaching. My understanding is, in either case, that there isn't any THC in the white area to speak of.
A guy on another forum trimmed all the white tips, dried and cured them together. Looked really cool, like space dope. However, said it was OK tasting and didn't feel a thing.
I dont know if this helped or made things worse but, according to some real(claimed) plant experts its an led thing, more prone to happen in certain phenos, but doesn't seem plant specific.