I've installed Ubuntu (almost all latest versions), when my Acer Aspire V5-471 is want to shutdown from Ubuntu, it acts as restart/reboot. Refer to edit 2 for releases tried and edit 1 for tried derivatives.
edit 1: It's happens on 2 versions (till now), Ubuntu and Ubuntu Studio/Xubuntu (both Ubuntu-studio and XFCE session).
edit 2: Same as edit 1 (only for live-user, others only uses Ubuntu), happened on Normal installation (12.04 to 13.04), Wubi installation (12.04 only), and Live User Session (12.04 to 13.04).
Rebooted after short shutdown time even as
sudo-ing from this command :
shutdown -h now
Why? Can I fix this?