Fruit blossoms w/o stigma, style, or ovary

My two-year old Flavor Supreme pluot has very sparse flowing, presumably due to the lack of chill hours this winter. But close inspection of the blossoms revealed that a significant number of them were lacking pistils (stigma, styles, and ovaries). I did not find this to be the case on my two other pluots’ blossoms. Does anybody know what might explain this? Could it be the lack of chill hours?