I noticed an issue where my prison was slowly filling up with prisoners sitting in their cells awaiting solitary, but not tagged with TODO: Escort Prisoner to Solitary, and manually selecting a free guard and right clicking them did nothing. I checked all the possible causes -- I have free guards, I have solitary cells, they're accessible -- and finally found the cause when I chanced to watch it happen live.
If a prisoner commits multiple misconducts at once and the offenses are tagged with different punishment types (i.e. the prisoner attacks staff with a weapon, and Attacked Staff carries a penalty of 2 hours in Solitary and Found Weapon carries a penalty of 1 hour in Lockdown), they'll be locked down appropriately and serve their time -- but that's it. They then stay cuffed in their cell forever with a Solitary sentence to be served.
Saving and reloading the game did not clear the issue, nor quitting and restarting. I've attached my save file.
If a prisoner commits multiple misconducts at once and the offenses are tagged with different punishment types (i.e. the prisoner attacks staff with a weapon, and Attacked Staff carries a penalty of 2 hours in Solitary and Found Weapon carries a penalty of 1 hour in Lockdown), they'll be locked down appropriately and serve their time -- but that's it. They then stay cuffed in their cell forever with a Solitary sentence to be served.
Saving and reloading the game did not clear the issue, nor quitting and restarting. I've attached my save file.