Not sure if this has been reported before, but found a new weird/cool bug/feature. I'm on 5.6 test4 ROM with Nova Launcher btw.
1. Enable Auto-Rotate using the toggles in the status-bar notification menu.
2. Goto home screen, turn phone to Landscape position. Nothing happens right? The screen stays in Potrait position.
3. (While still holding the phone in landscape position) Open any app that supports Landscape viewing.. say Phone or Messaging.
4. (While still holding the phone in landscape position) Pull down status-bar notification menu and disable the Auto-Rotate.
5. Goto home screen now!
The phone is stuck in Landscape positioning now.. even the previously portrait-only homescreen and app-drawer are now reorganized in landscape mode.
A pseudo-tablet mode!
If you switch on Auto-Rotate... get landscape mode(using any app that supports it) and then switch Auto-Rotate off while holding the phone in the same position.. the phone remains stuck in Landscape. A slightly buggy home screen but I like it!