Twilight of Darkness

There seems to be something wrong with this rating system. You fulfill their requests, increase your rating, and suddenly, with 40% trust, they declare war on you. I thought it was random, so I replayed the turn. Same thing happened. At the same time, the other two factions have a rating of -30% and nothing happens – they remain at peace. I didn't even see the Elves when they declared war. I think there should be some pattern in the AI's actions, relative to the rating. Otherwise, it's useless – just kill everyone.