My FreeNAS auto restarts on shutdown (if started with WOL)?

[Vectorspace]

My new (and first) FreeNAS box has a peculiar bug. When I shut it down (either by Web GUI, poweroff/shutdown command over SSH, or the REST API), it will often start itself back up again. Then if I shut it down again, it will stay off.

I do not mean it reboots instead of shutting down. I mean it shuts down - fans off, power LED off - and then after about 3 seconds it spontaneously starts up again.

I have no idea if it's FreeNAS or the motherboard or something else. I have tried changing the CMOS battery, I have not tried flashing the BIOS.
The BIOS setting for auto power on after AC power loss/restore is disabled, as is power on by mouse/keybvoard (though it does not have either plugged in anyway). Wake On LAN is enabled, and I use this to remotely start it when required.

Does anyone have any theories?

Edit: Added "if started with WOL" to title

 

[Glorious1]

Try disabling wake-on-lan. If that fixes it, and I'm guessing it will, you need to figure out what on your network is causing it to start.

 

[Vectorspace]

I can't - the option is missing from the BIOS. Seems to be a common bug with this motherboard (Gigabyte GA-Z77X-D3H), but I am on the latest release BIOS version and I don't like the idea of downgrading or installing a beta BIOS.

I do agree that it is Wake On Lan related - I have now determined that it only happens if I power it on with WOL. If I powered it on with the power button, it does not happen.

Someone on the Gigabyte forums suggests it may be power config related: https://forum.giga-byte.co.uk/index.php?topic=23151.0
But I have no idea if/how that applies to FreeNAS