The fact that it previously flowered normally is interesting. I know that genetic variation occurs sometimes from flower to flower on one raceme or panicle. Spotting patterns, in particular, can vary a lot from bloom to bloom and some flowers can be either normal or abnormal on the same stalk. In your interesting anomaly the pattern for the petals and dorsal sepal got switched around. It would probably be explainable as a random mutation resulting in a peloric flower which may or may not be repeated. Some species and hybrids are more unstable than others but normally, P. sukhakulii is very stable. You have a plant with a rare tendency to mutant genes as expressed in the flower. I would save copies of your photos and compare them year to year just to see how great this tendency to mutate is and to record the variations: of some scientific interest!