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: playing ironman mode, some scene block the player from exiting the game (probably because the game doesn't allow to "save" there ?)
How to Reproduce: ironman mode, go into arena in a town, press escape key, only option is "exit to main menu" and is greyed out. no "save & exit".