I also own a D34010WYK and setting Deep S4/S5 does not help - it still reboots after shutdown. If i connect a USB keyboard it does work but since i have attached the nuc via vesa mount on my tv i cannot attach a keyboard for normal operations. I tested this behavior with the latest (24) bios. By the way - as soon as i try to change the S3 Power button state (on/off/blinking/other color etc.) the bios crashes for me and i need to reboot.
I hope we see a fix for it in bios 25 ... if you need my help on anything (bios setting / etc.) just drop me a mail.
Martin