It seems that whenever a battle occurs and all elements from side are wiped out and there is a leader, the game crashes.
The game displays two error messages, one followed by another.
TSubUnit.IsCadre John Glover 1000806 don't have a cadre but is at cadre level.
TBattleEngine.MakeAttack while picking a sub unit: Erroneous logic
As a little back ground John Glover is the commander of a besieged force that was assaulted and lost all the non supply units he was commanding.