You can attach photo here. Environment was the cause, pistils is only esthetics, no influence to harvest. They shrink when being polinated, check for male flowers, maybe plant went hermie.

Hey! Don't worry, it's something that can happen. The most common reason your plant's pistils may have shrunk in size could be water stress. When plants are left without watering for a while, they can enter a state of stress. When you water them after this period, they can react in different ways. Another possibility is that the environmental conditions during the day, like direct sunlight and heat, may have affected the plant after watering. This can cause the plant to lose water quickly, which can also influence the appearance of the pistils. I recommend going back to your nighttime watering routine and observing how the plant responds. Also, make sure the plant has the right light and temperature conditions. If you see the problem persists, it might be helpful to research more about the specific needs of your plant's species. Hope this helps, cheers!