This is probably fairly common, I'm not sure, but it still bugged me since I'm worried about losing my position.

Saxony used to support me but I pissed them off somehow.
On an unrelated note, I HOPE 1.3 FIXES THE SUICIDAL AI. I am so tired of 10+ minors inviting me to crappy alliances just so they can DoW their uber neighbours the second I agree. Denying it kills our relations, and accepting it thrusts me into idiotic wars that I have zero interest in fighting. Best examples:
1. One province Corsica DoWing a Tuscany that controls every province on the Italian peninsula the second I ally them
2. Five province Venice DoWing a massive OE the second I ally them
3. Two province Norway DoWing a Sweden that controls all of Scandinavia... and has Austria and Lithuania as allies. Once again, they do this the second I ally them
The list goes on...