marjo: Thank you very much for contacting the Intel® NUC communities. We will do our best to provide the information you are looking for.
In regard to your inquiry, I just wanted to let you know that we tested that same NUC in our lab and the issue was not replicated, the light never went off in hibernation. I also looked on the released notes for BIOS 0054, and there are no comments in regard to this matter:
So, please try to re-install the BIOS version 0054 using the F7 method to try to fix this problem:
Any further questions, please let me know.
My suggestion would be to reinstall the latest BIOS, but this time using the jumper-based BIOS Recovery method.
Once the update is complete, use F2 to enter BIOS Setup (the Visual BIOS (VB) program). Press F9 (followed by Y) to reset The BIOS configuration. Then, press F10 (followed by Y) to exit VB with BIOS Configuration save.
During the subsequent POST, again press F2 to enter VB. Now make whatever BIOS Configuration changes, including LED programming, that you desire/require. Use F10 (followed by Y) to exit VB saving these changes.
Now test the Hibernation entry methods...
Note: do not combine the two BIOS Configuration change steps. The BIOS Configuration save and re-POST in between *is* important.
Hope this helps,