Please note that we've updated the Mount & Blade II: Bannerlord save file system which requires you to take certain steps in order for your save files to be compatible with e1.7.1 and any later updates. You can find the instructions here.
Summary: I go to the castle where I can find lord I want to ask to join my kingdom
But castle is under siege by army of my vassal
Game asks me if I want to join the siege
I go to kingdom tab and declare peace
Game crashes when it supposed to go back to main map.
How to Reproduce: use my save...