This has happened a few times. Every time AI has large scale Armageddon coming my way and i am about to blow em into oblivion, i come to find AI building units/structures, but AI's offensive freezes to the point that it cannot even defend. Long detail short, I make system, I make sure no experimental, no more then 3 planets, nothing maxed out or near.
The AI is still a work in progress. it has some issues depending on its start. But most of the time if it gets a good area to start in it will flatten you.
