Hard to say. If the plant that the seed came from was super healthy and there were no males around it is likely there is a genetic tendency at work. However, even very stable genetics with no genetic predisposition towards hermphrodism can throw out nanners if under excessive stress. Poor plant health during flower sends the plant into a state where it pushes out some male pollen in a last ditch effort to reproduce. So again, it is hard to say without more info.