Feminized seeds passed along at meetups or through forum swaps come with no guarantee about how they were produced. If the source plant was a stress hermie rather than a properly reversed female, those seeds are far more likely to throw pollen themselves. Some questions worth asking the person handing them over are outlined at https://queenfeminizedseeds.com (https://queenfeminizedseeds.com) along with signs that a batch might be unreliable. Free genetics are fun, but I keep them away from my main run until proven.