I'm playing as Stalin, and I get a quest to obtain a source of horses from the Mayans. So I set about conquering the Mayans, and eventually I manage to conquer their last city, which contains the horses. I get a message that says "The Mayan empire is destroyed!" and immediately failed the quest since the horses didn't lie within my cultural borders. Quite frustrating since that was the reason I declared war on the Mayans in the first place. The conditions for failure of the quest should probably be changed.
EDIT: sorry, I pressed enter before typing out a thread title...
EDIT: sorry, I pressed enter before typing out a thread title...