I'm also having this problem. Everything was going well with 40 or so prisoners, so I extended the land and added a new cell block to start taking some lower security ones in too. As I was finishing building everything I realised loads of fights were kicking off where they'd started to move in to the new cells, on further inspection I see it says "Lockdown" in the top right but bangup and lockdown are off, with showers and eating in the actual regime. I can't find a way to let them move around again, restarting and toggling bangup makes no difference but they're just getting enraged then destroying things otherwise.
Edit: I have found a fix on Reddit. The following worked for me:
- Save the bugged game and do not use the cloud
- Type "%localappdata%" in the start menu and press enter to open the folder
- Browse to the folder Introversion > Prison Architect > saves
- Create a copy of your prison save file and edit it in Notepad
- Press CTRL + F to Search, type in "Bangup"
- Edit the line from "true" to "false"
- Save the file, open the game and load the copy you just edited