Not sure about the baking part, but Elegant Cheesecakes out of California has been wrapping their cheesecakes in modeling chocolate and what they call "chocolate paper" for at least ten or fifteen years. Good luck!
My "blue" velvet turned out a rather funky army-ish green. Great if I ever need a camo theme. But if you really want blue, just remember what the cocoa will do to the food coloring. That said, I'm way on the novice end of things, so that could be part of it.
I would also love a reason, but don't really think there is a concrete one. I have baked four dozen cupcakes from the same batter, in the same wrappers, and in the same oven and had anywhere from 0-3 from each pan pull away. So anything I've tried to decide was the culprit never held up. I decided it was punishment for past sins. :)