Hello, celtkirk. I would not worry too much about it if it is just one double leaf. It could be problems due to drifting of insecticides & fungicides or it could be an error in the genes. Camellias hybrids sometimes have flowers of different colors on the same shrub so I assume the color issue is some form of DNA predisposition that creates a sport in a section of the plant only. This type of problem does not happen to all camellias but rather to selected varieties.

I have C. Shishigashira too but I have not noticed the double leaf pattern in your plant. I will try to observe it more closely as soon as a reseeding annual vine that is entangling it dries out for winter; I can barely see the thing from afar now but I know it is there... Hee hee hee.

Luis