I'm highlighting this defect again (as others have in the past), as I am not aware of the v1.1 optin update details between June 17 and July 9 (final V1.1). This defect has a very large impact to the game, due to the fact that as long as you are victorious in your invasion, no consequences are given to the attacker. Hence, an unfair advantage to attacking races, or those races that first develop planetary invasion technology:
The final population of the conquered planet should be 4.1, however the invader casualties are not subtracted from the new population, resulting in an erroneous value of 5.5, a ~25% population increase in this particular example.
I would hope this to be fixed quickly, as it is both a trivial and significantly impacting defect.