Lesso has nailed it. The problem with using seeds from a plant that selfed (hermy seeds) is that the seed are genetically predisposed to hermy. They don't need any stress to start popping nanners and pollinating your crop...as you have found out. They can and often grow right inside the buds and you might not even see them. We are kind of thankful for their yellow color--it makes them easier to spot. You can have this happen even if you did everything right. It really doesn't matter if the bag was quality smoke or dirt weed, hermy seeds are hermy seeds. In fact, I'd be more inclined to believe that the seeds in swag were created the old fashioned way as little care is taken to make sure that all males are removed in big guerilla grows.
Good quality seeds are simply not that expensive, especially when you consider what you get. When you buy from a reputable breeder, you know what you are getting. You know what to expect from the strain--the type of high, how big the plant will get, how long it needs to flower, whether it is a heavy feeder or light feeder, etc, etc. You can get seeds that have the attributes you want. And then once you have a nice stable strain, you can clone to your heart's content. I picked up an Indica from a dispensary a while back that I really liked, so went looking for seeds so I could grow it myself. Sent off the order on Monday--expect the seeds in 7 to 10 days--how convenient is that!
Your plant looks really nice. You did a great job! Now get out there and find some great genetics that appeal to you and really kick some @#$. You won't be sorry.