This is probably a one-off thing with your particular supply; what's worse are the ones that don't always want to turn *on.*
However, it's also a programmable feature on many x86 boards, either via jumper or BIOS - "Power on after interrupt?" or somesuch option. It comes in handy for embedded appliances and non-UPS-backed servers -- you don't want those sitting idle; back in the old days, you'd just leave the power switch "on" and there was nothing more to it.
It's possible that, given the 'server' intentions of the original Teron designs, the A1 is designed to do this, and/or there *is* a jumper to set somewhere. Read the manual, ask Eyetech?
Simple solution is to put up with it once, and leave it plugged into the wall, as it should be. Now that we have ATX supplies, and monitors that go to 'sleep' without signal, there's no reason to be flipping switches on a power strip. A properly designed monitor and turned-off ATX computer (with the small amount of current still trickling to allow things like Wake-on-Lan, and the power switch itself to work) shouldn't draw more current than the average nightlight.