- If the current population is >= the population cap, then the various Assembly jobs (which create population) are grayed out. This is good.
- If the current population is < the population cap, then the various Assembly jobs can be queued up. This allows races using the Yor tech tree to create massive amounts of overpopulation. The disadvantage, of course, is that it hurts morale on that planet, but bad morale in exchange for an infinite source of population and soldiers might be unbalanced.
#2 might be by design, but given #1, I don't think it is.