Real Hermis tend to make more hermies. The issue is you currently created them because to stressed them out. So if you stressed out a regular plant and got a hermi then unless you figure out what went wrong, it is likely you will have it again because it just keeps getting easier.
The flip side is this wasn't a regular plant this was a femd seed so that is a chemically induced hermi if it came from a reputable source. I am running my first Fems now so I have little experience here but my understanding is they are more sensitive and easier to make into a hermi to begin with. So you may have conditions that a regular plant might have gotten through just fine. So you may be by the book but just a little too rough for such a sensitive stock.