The other two times, I am guessing, this had buds and blooms that were different, normal?
One thing I can say, after many, many years of growing plants, is that plants will occasionally do weird things that they are not supposed to do, for no reason that can be discerned. Sometimes, though, the growing conditions are suspect. If the plant is healthy, the blooms should be normal next time.
Well, enjoy whatever weird thing happens and hope that it will be normal next time.