Its a great question, my outdoor grows great with no Herm's and not only is a full moon extremely bright..I have cars that drive by and use their brights on my dark road.. The lights definitely hit the garden.
sure, we are often told many things...light leaks cause hermies, nitrogen during flowering makes it stretch, you need high dosages of phosphorus and potassium during flowering, bud hardeners, flushing additives..
Been growing for yrs and yrs, and they are many things that in "
theory" may, or may not happen, or be something that could occur, but in practicality/ the "real world"?
Well, just not in my experience.
I have the same experience as you, many times my plants are subjected to odd lights, VERY bright moon (on top of the mountain)
I think 90% of the time hermaphrodites are simply genetics.
I'd say higher than 90% but who's to say