I get the same issue

Similar problem, just stays near one city, more like in city. cant do anything, disband doesnt work

This is a known issue they haven't fixed yet. Your only recourse is to use the console, you need to turn on cheats in your /My Documents/Mount & Blade II Bannerlord/Configs/engine_config.txt change this line
cheat_mode = 0
to this
cheat_mode = 1
save it and launch the game, load into your save.

Activate the console with alt+` and use the command
campaign.make_hero_fugitive Character Name

where Character Name is their name as it appears in the character and clan screens etc. So if they were called Maki the Swift you would use
campaign.make_hero_fugitive Make the Swift

The game will act as if the party was captured, with the leader escaping and regrouping. They will then reappear somewhere after the usual amount of time for that. Then you can reform the caravan. I don't like doing it but it works.

I like to turn cheat mode off after doing it (close the game after saving, open engine_config again and change 1 back to 0 and save it) because the free units in the party screen are real tempting.

Also, if you're on proton, you'll find the file at
/SteamLibrary/steamapps/compatdata/261550/pfx/drive_c/users/steamuser/My Documents/Mount and Blade II Bannerlord/Configs/

Some desktop environments bind alt+` to something, KDE Plasma did in my case, for cycling through windows within a program group. Unbinding that in the KDE settings made it possible to use the console.

Originally posted by Draco:

This is a known issue they haven't fixed yet. Your only recourse is to use the console, you need to turn on cheats in your /My Documents/Mount & Blade II Bannerlord/Configs/engine_config.txt change this line
cheat_mode = 0
to this
cheat_mode = 1
save it and launch the game, load into your save.

Activate the console with alt+` and use the command
campaign.make_hero_fugitive Character Name

where Character Name is their name as it appears in the character and clan screens etc. So if they were called Maki the Swift you would use
campaign.make_hero_fugitive Make the Swift

The game will act as if the party was captured, with the leader escaping and regrouping. They will then reappear somewhere after the usual amount of time for that. Then you can reform the caravan. I don't like doing it but it works.

I like to turn cheat mode off after doing it (close the game after saving, open engine_config again and change 1 back to 0 and save it) because the free units in the party screen are real tempting.

Thank you. It works :)