Curses!
The office screen ending past a certain date was meant to be a backup in case the normal one didn't trigger. The canon ending is getting put in a holder after having failed to meet production quotas (and the game's goal scaling is designed around this outcome, make a playthrough last long enough to see most of the content but eventually lead to failure).
The end screen hiding the epilogue is normal at least. Acquiring the warden ends the prison event line but she will get an acquisition scene + recurring inmate offers under the "new leadership".
Thank you very much for flagging what you didn't see, most of these had faulty conditions and/or continuity issues.
I apologize for those technical issues and thank you again for playing and pointing them out!