My tributary Ayutthaya allied with my rival Ming. First there's a couple of bugs, I declared war against Ming and while it showed a red X next to my tributary he still joined in the defense and I lost him (hovering over the X actually says that he will join). Then to make matters worse, the option to enforce him as a tributary again is greyed out even though there's enough war score. The reason given doesn't make sense but it's probably related to the first bug. So I white-peaced Ayutthaya and now he allied another tributary of mine which I'll lose the same way if I declare. I can't Break Alliance because he's a subject. So what's the best way to deal with this kind of situation. Are there any tricks?