Hmm well I know some corals, such as the Kenya tree go through like a molting process every so often..mine just did it last week where it closed up, turned white and looked as though it was shedding and then over the weekend it was back to normal..I would just keep an eye on it and your ammonia levels
I took it back to the lfs over the weekend and they have me a new one. Good info on the Kenya tree though thank you