I have the same issue after a forced shutdown due to critical battery: It seems that in this case the session is automatically saved.
When I
1. turn on the option "Automatically save changes to session" in the System -> Sessions dialog
2. close all windows to get a empty desktop
3. log out and log in with the result: the desktop is empty (like expected)
4. turn of the option "Automatically save changes to session"
5. log out and log in with the result: Session manager and nautilus window open automatically after the login
I have the same issue after a forced shutdown due to critical battery: It seems that in this case the session is automatically saved.
When I
1. turn on the option "Automatically save changes to session" in the System -> Sessions dialog
2. close all windows to get a empty desktop
3. log out and log in with the result: the desktop is empty (like expected)
4. turn of the option "Automatically save changes to session"
5. log out and log in with the result: Session manager and nautilus window open automatically after the login