LattePanda Delta 3 Auto-Power on with USB-C power

I have just received a number of systems containing LattePanda 3 Delta boards that I need to get cleaned up and all working properly again.  I have never worked with these particular boards before. 

So far only one of three of the systems (that I have worked on so far) will auto-power on when using the original USB-C power supply, even though the BIOS is set to power on after AC loss.  They will power on when you press either the small "POWER/SW" button or the switch next to D13 (the original builder brought that out to an external push button).  My search of exactly what these buttons are supposed to do have not been terribly fruitful!

The USB-C power brick is rated at 65W but we know that's not always whole story. 

Just now I hooked up a bench supply to the board and wired it to the 12V input pins and the board powered up and booted as it should without my needing to press any buttons. 

Is there some jumper or setting that I have not been able to find?

Or is the USB-C power brick somehow not as good as it should be?

Thanks!