Your mother plant may not turn hermi, your clones may be succeptable to stress forcing a hermi. Basically the seeds you buy have been dipped in hormones to force it to be female. I think colloidal silver will do the same as well. When they do the hormone treatment it alters the genetics a bit, it can produce some crazy buds too. Farmers have been doing it for years with corn and other crops. It should not go hermi on it's own though.
Just speaking from experience, other results may vary.