Why is the AI so dumb?

I'm playing a game where when I die I observe for a while before taking control of my empire again. I noticed the ai do something really dumb they keep moving the capital from where I keep it. I set my capital in Hamburg it has 4 castles 2 cities and a church all fully upgraded a level 6 hospital and max technology. But the ai right now moved it to pfalz where at best 5 buildings are about halfway upgraded and a third of the technology.

Edit he just moved it to anhalt