actually, this isn't really a bug, well maybe it is but, you can keep the production of seedlings by moving seedlings to other asteroids constantly to build up a mass. The asteroid with over the limit population count do not produce more seedlings but, it can hold more seedlings from other asteroids without a limit as far as I can see. It is easy to mass a giant group of seedlings up to 300-500. I do it all the time and win fast.