Me and a friend tried playing together recently and I noticed something strange with the AI the two times we fought against the AI. Even on hard difficulty, the AI would barely build any ships and be very slow at colonizing. Many of their planets very close to their homeworld still had neutrals left in them and they never attempted to take them.
Can lag have anything to do with this? At the start of our matches, it usually speeds up the game for the first few minutes then goes back to normal speed and I read how that is caused by lag.