Hello AlexanderR, I’m sorry for the inconvenience that you have faced with your NUC.
This behavior looks like a BIOS issue, so I would recommend you to roll back to the previous BIOS version and check if the behavior persists.
If it does, please get in touch with our Warranty Department so they can help you to replace the unit: http://www.intel.com/p/en_US/support/contactsupport