Sure Sylvia:
NUC model: d34010wyk (+64GB Kingston mSata SSD +1x 4GB RAM)
BIOS: latest (0033) -> i also i tried v28 and v30. same effect
Devices connected: Logitech Harmony Smart Connect keyboard via USB (same effect, when i plugged out the usb-connector)
OS: Win 8.1 64-Bit Prof. All Updates installed
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After a lot of more reading and testing i have some new infos. my problem with the xtensible host controller depends on the intel gigabit ethernet controller. when i plug off the ethernet cable the nuc do not restart after sending it to standby, as soon as i reconnect the cable it wakes up. i now disabled all WOL-features from the ethernet adapter and it seems, that its working. but im not satisfied because i need WOL. ill try further and come back to you guys