Regarding the problem: 
What is probably happening is that your computer goes to sleep so 
fast that it's already asleep when you release the button. Which, in 
turn, makes the IR receiver create a HID event, which in turn, wakes 
up the machine again.

As a temporary fix: release the button promptly ;-)

As a general fix: I'll add a delay of a second or two in Remote Buddy.

Thanks for pointing out that problem!

Best regards, 
Felix