I find the most common reason for AI bankruptcy is prolonged wars, not minting as such. It happens when most of their provinces are occupied and they no longer have any way to pay or reinforce their armies that were raised to match their old pre-occupation support limit (they seem unaware that the force limit is changed as soon as a province is occupied).
Not sure how one would solve that problem though. As it's generally not a good idea to disband troops when someone is holding some of your territory in a war. With the AI the situation can get ridiculous though with it keeping troops many, many times it's support limit around with no prospect of actually retaking provinces anytime soon.
Not sure how one would solve that problem though. As it's generally not a good idea to disband troops when someone is holding some of your territory in a war. With the AI the situation can get ridiculous though with it keeping troops many, many times it's support limit around with no prospect of actually retaking provinces anytime soon.