Nothing is 100% guaranteed when dealing with living beings that have been chemically induced to alter their genetic make up, ie - feminised seeds.
It is quite a rare occurrence, but does seem to happen more often with auto plants for whatever reason. After looking at your diary, you certainly apply what I would consider "extreme" lollipopping and mucking so much with a plants metabolism could also be a contributing factor. Not sure why you are removing so much growth for and reducing your harvest potential greatly, but continual topping combined with extreme lollipopping may have caused so much stress to your plant that this has occurred as a result. You would be far better off planting later in the season, if height is an issue, rather than planting earlier and continually traumatising your plants with the extreme lollipopping methods you are subjecting them to. To have plants that are already 15 weeks old and have only the last 3-4 weeks of growth on them is no doubt causing major metabolic problems and it is a wonder you have not had more issues really. I don't see any point of having 4 month old plants with only the last months growth in place, it seems like a big waste of effort for the plants. Like I said, if space/height limitations are an issue, planting much later, around/just before the summer solstice, will give you plants that grow fast, flower fast and stay reasonably compact, around 3-6 feet depending on the strain and combined with some training to keep them low, you get a much more natural life cycle, without the need to constantly trim growth off.
Anyway, each to their own, but late planting is a really good way to have many smaller plants with plenty of variety and without the need to prune them, apart from a little lollipopping at the onset of flowering. To grow big plants and then remove 80% of their hard work with extreme lollipopping is odd, in my opinion.
To have feminised seeds go male is a bit unusual, however it does happen from time to time, as you found out, but I can't help but feel that the growing methods you employ are part of the reason that this has occurred, due to the constant one step forward, two steps backwards effect, that you are subjecting the plants to. What may be a proven method for indoor growing, may not be an ideal cultivation technique for outdoor plants, especially since they can get sunlight to almost every part of the plant, making heavy lollipopping not as beneficial as when growing indoors with a static light fixture.
Hope this helps,..... Organoman.