The AI never seems to use planetary bonuses. I have seen planets with approval rating bonuses and the AI decided to build factories on them, it then decided to build multi-media centers on the other plain tiles. The AI actually uses the bonus tiles about half of the time.
I see this type of mismanagement everywhere and I play games on "challenging". The AI could actually be tough at this level if it actually knew how to build infrastructure.
I have seen orbital defense systems of PQ4 planets, seriously!