It is not returning to previous psm state or does not know what is actually "previous state"... if it swapped through different cases it will get stuck on the one before so if previous case was "idle over night" and next case is default it will go to "psm-active". Going to Settings->Device->Battery *bling* psm turns off. EDIT: Ringtone is kept off as well.

My girlfriend asked me about alarm-clock setup as she was interessted what I do with my mobile running around in her flat^^ don't know how easy it would be to alter "on-off" states of alarms depending on where I am?!