The original conversation was closed and locked for some idiotic reason, so I could not explain what is going on. I am opening this conversation as a replacement for it.
I received an explanation regarding this issue from the development team. This is NOT a case of the setting for this parameter not being saved. In fact, the setting *is* being saved. The reason why, when BIOS Setup is reentered, this parameter displays as not being enabled (not checked) is because the Thunderbolt IC is also enabled and it does not support this feature. If you disable Thunderbolt IC support, save and reboot and then enter BIOS Setup again, you will see that this parameter is now enabled (checked) again. Remember that this IC is used in other NUCs, so the same operational differences exist with these other NUCs as well.
So there's your answer. Not a bug but a feature. Unfortunately, a horribly confusing feature. I would have preferred that the BIOS immediately display an error message indicating that this feature cannot be enabled while the Thunderbolt IC is (also) enabled.
Thank you for your feedback and the information provided.
We are currently working internally on that specific case, but we will unlock the original thread and post the response soon.
I will proceed to close this thread.
Intel Customer Support Technician