I have a 14 pb Cattleya Artic Star 'Snow Queen' that has been blooming w/o sheaths, but the last three pbs are producing sheaths. They are not far enough along to be showing buds. Why is the plant changing over its flowering technique? I bought the plant last Oct, it was in flower, but none of the other 7 pbs showed signs of sheaths.

I'm growing it outdoors in the shade of trees in an 8" bulb pan.