I haven't had time to test this yet, so I apologize if it is not actually something to be fixed

I noticed that on one of the huge maps, there is a single planet in one of the solar systems. This planet has a neutral factions occupying it, along with several military forces.

I'm assuming this planet is for "King of the hill" victory condition.

When you research (as the Rebel TEC) the tech that allies you with all the remaining rebels, you (presumably) cannot attack this world, and as such, cannot win by "holding it"

Again, please correct me if I'm wrong.

A way to bypass this might be an option to "break" your alliance with a certain Neutral faction in order to claim this unclaimable planet which is needed for victory.