Mine behaves like that too, though I have permission to write in these folders and can change my config. I admit I don't understand Windows behaviour in this area!
I presume you can save games? If so then the overall permissions on the Bannerlord folder are probably okay. If there's a problem it's in the configs sub-folder. Make a copy of that for safety, if you like, then try editing BannerlordConfig.txt with a text editor, add a space at the end, see if you can save the file. If not, you have a permission problem and you'll need to solve it (sorry I'm from a Unix background and my Windows knowledge is sketchy). If you can save, delete the space and re-save, or restore your backup from earlier.
Other things you could try:
- look at the Modified dates on the config files, that will tell you if the game is actually writing to them.
- if you can edit the config files with a text editor, make the changes you want that way. In fact, make a small valid change and see if Bannerlord overwrites it with the defaults next time you start up.
- delete the whole configs folder (back it up first) and create a new empty one. Or see if Bannelord creates a new working one.
- explore the Windows events log for any errors or warnings that happen when you start up or shut down Bannerlord (just type "events" in the Windows search bar).
- reinstall the game
- any information you get, pass it to the developers.
