Hey there,
I've seen more people report this issue and i also seen it is known by Taleworlds under known issues
Been experiencing somewhat similar crashes.
Basicly getting: "the application faced a problem" after a short delay/freeze in game whenever i click 'Done' at the battle(score)screen. This was not a siege, but normal battle (lord vs lord on world map). Doesn't matter whether or not i fight manually or auto-resolve. Reloading the save (5+minutes before) doesn't help either.