Sorry, but If have the German version. I was in the extreme energy saving mode from the Sense 6. And I couldn´t go back to "normal" energy mode.
In the end I long hold on home button and searched Einstellungen" (settings) and switched back.
But at the extreme energy saving mode was no opportunity to switch back.
Hm....strange
Flash the rom again and make wipe
Perhaps this could help
If I turn off Bluetooth, my phone does a soft restart, also at planemode.