I have many 5i5RYH out "in the wild." The majority run Linux Mint 17.2. When those systems' monitors sleep, the NUC wakes them up with user activity (i.e. KB, mouse, IR, etc.).
Not so with monitors connected using Display Port and with the NUC running under Windows 10.
This thread: NUC NUC5i5RYH HDMI Sleep Issue
seems to indicate the problem is solved with similar issues related to the HDMI port.
Unfortunately, I verified this problem still persists (today) under the following (very up-to-date) configuration:
NUC 5i5RYH
BIOS: RYBDWi35.86A (latest)
Intel Display Driver: 15.40.10.4300 (latest)
2 (HDMI) monitors connected with Belkin Mini-Display Port to 2x HDMI dongle (the adapter can be seen on Belkin's page here: F2CD059 | Belkin Business )
Intel or others, please confirm you see the same problem and advise on driver progress. Is this known and is a beta driver available?