There is a bug connected to using "information warfare".
Let me explain at an example:
Invading a 16bn-planet with a morale of ~50% yields you ~1600-3200 aditional troops. So far so good.
If your invasion succeeds - still no problem
If it fails and you attack again right away in the same turn the bug "strikes":
Despite the population being lower they still have the same low morale, which allows you to use "Information Warfare" again.
This could still be considered "working as intended", but if you save the game after the first attack and reload that saved game the morale gets re-calculated and it's now higher (Most likely 100%)
Either morale should get re-calculated after each attack or morale is constant within the same turn then it should still be low after you reload the game.
This came into effect quite drastically when I invaded a 16bn pop world with 47% morale and had 3000 troops available (2 fleets with 1500 each)
If morale had been re-calculated after first attack I would have had no chance whatsoever of invading that planet (as I didnt have a major advantage in strenghth (Maybe even a disadvantage)). But as I could use the additional troops twice I succeeded.
Afterwards I tried it with saving inbetween battles:
First attack dropped pop to ~5bn. For immediate 2nd attack morale was still on 47% and I could gain troops from info-warfare.
If saving game after first attack and reloading that - morale for remaining pop is 100%.
Maybe that's nothing gamebreaking and nothing major, but imo morale should get recalculated after each attack. From a "reality" POV I would even say morale should always be set to 100% after there was an (unsuccessful) invasion - as people are now aware that some foreign force wants to grab their planet - and they stand together now despite previous unhappiness. or some such.