I've got this exact thing going on right now with my Purple Cookie. It threw me off, because when I first saw the yellowing, I thought I had somehow burnt my plant with some nute issues in my soil. I let it go, and now she's 25 days into Veg and she looks FANTASTIC! The half yellow and half green leaves appear to be on one cola at this time, but we'll see what happens. I'll try to get some pictures so people can see the beauty of this odd situation. What's really strange is, the albino leaves are so healthy and vibrant! The buds from this plant should be VERY interesting!