Quite often a female will produce a seed or two which doesn't make it a hermie but does mean it had a male flower early in its life, or one nearby from another plant. Or possibly you transported a bit of pollen in from a friend's grow...but no matter. If it came from a self-induced pollination I would save them and grow with the next batch as the few I have gotten over the years have always been female when grown out. You'll know when the seed's ripe by watching for the pod to split but do not use it as a judge on when to harvest. These seeds usually happen very early in the plant's life and are in no way connceted with the timing of the crop.