I am trying to play the Gaian Crescent 2-player scenario with Advent, but I think the problem is similar for any race.
You start for some reason with allegiance of 25% limit instead of usually 100%. It does not increase over time either. That means practically 0 income (actually it is negative untill you develop planet population to the second level, then it is 0.7/sec). You have just enough money to build capital ship and that's it. You economy is dead, and all you can do is to protect your planet from the pirates and wait literaly forever to build at least one reseach station. You can't even colonise anything else, because you will not have money to develop that.
Is this scenarrio bugged?