In my game, Milan just annexed Trent, a HRE member OPM. As emperor, I obviously want them to release it again, but I cannot see the option available in the peace treaty dialog. Trent still has full core on their former province, so it shouldn't be a problem.
What's up with that? Why can't I demand release of Trent? Screenshots of the situation attached.
What's up with that? Why can't I demand release of Trent? Screenshots of the situation attached.