Official Response from The Behemoth:
We have confirmed that the Jail Breaker achievement not unlocking is an issue that will require a fix from The Behemoth, and apologize for any difficulties or frustrations this may have caused anyone. We are currently looking into possible fixes and a timeline.
Thanks everyone for your patience on this issue!
There are reports of several players around various gaming communities that it seems nobody is able to unlock the achievement for freeing 50 prisoners at this point. Is this something you are aware of and/or have a fix for?