Firstly when did you last repot your Massies, I recommend between every 1-2 years, or have you recently moved your plants to another location this is called a micro climate remember they get used to their environment. I also find long periods of cloudy days and cooler temperatures in early spring can change the blooming habit of a plant, this can also happen if the plants got too warm during the summer months, hope this helps a little and good luck.