Hello everybody,
....not strictly a bug -- but IMHO at least an oversight / edge case worth discussing.

Question: When/why is an enemy's resignation in a war putting me at a DISadvantage?
Answer: Whenever one owns the "Opportunity Ideology" highest capability "Poaching" ("Capturing a core world you keep the governor")

I would have been able to capture the remaining core worlds in a fairly short time and I would have kept all governors!
...governors that now cost me quite some money and - worse! - I am unable to replace at this very moment, because there are only two leaders of low/mid quality available for hire and my foe handed me quite some more core worlds than just two.
So should I have foreseen that and kept that many leaders "in reserve" - considering the quality of leaders available during that war and cost involved I'd rather not!