Oops - meant to also mention I have purchased Kona white @ Joanns for a couple of projects that needed solid white (I can stretch that far, lol) and have had no problems with it at all. There isn't much fabric I buy there anymore, but this was fine.
As far as winding fabric on bolts, it's possible that they were combining partial bolts for the sake of saving room. They often have several partial bolts.