Hhmmm, sounds like the support for headless operation within the BN BIOS is not working properly. Intel Customer Support (intel_corp) will been to investigate this.
BTW, as an alternative (though at a cost), there are monitor emulator plugs that can be inserted in the connector and thus avoid having to have the monitor present.
Hope this helps,
This message was posted on behalf of Intel Corporation
Rikibu: Thank you very much for joining the Intel® NUC communities. We are sorry to hear the NUC is not working as expected.
In order to try to fix this problem, we can try a BIOS update to the latest version which is 0050 using the F7 method:
Also, we can try to re-install the chipset and management engine drivers:
Any further questions, please let me know.