I was having an issue where the game would crash when I clicked "start rebellion" to launch an abdication faction. I replicated it many times with many different mod loads, including just diplomacy and its dependencies. Thankfully, the issue resolved itself after disbanding the faction and letting a long time pass in-game. I created a second faction and the civil war triggered and ended with no issues.

I hope that this info may help with development, this mod is so fun and well-designed, thanks for your work.

Link to report: https://report.butr.link/7850F2.html