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.
my feedback about troop tree of singleplayer:
tier III sturgian brigand has chainmail armor while their equivalents wear gambeson or leather armor.
tier III vlandian infantry does looks like germanic tribe warrior with that chest armor it should be changed...