There are of course strains that are more likely to hermie. But we have to attribute that to environmental stress. If you’re completely dialed in and nothing abnormal happens. You should never see a hermie. Check out this thread. That helped bring the ILGM zkittles issue to light. Hellraiser grows Zkittlez and Banana Kush in coco with Jacks 321
One seed means the plant got pollinated in one spot. An open window with a breeze can cause that. Another plant that is male or hermied within half a mile, can cause that.