First off I'm sorry if this has already been pointed out.

When you launch a transport and choose to fill it to capacity then land it on a planet with less than its capacity in population you'll lose the troops. Your troops seem to dissappear and you can't launch the ship again. I've had this problem a few times in my game, notably on planets with very low population due to their farms having been destroyed in invasions.

Anyways, not a big deal but its irritating not to be able to land your transport ships.

Awesome game overall