My facetious response would be "Yea, So?". Seriously though, this isn't a problem - unless there is more to it than you are actually saying.
In those NUCs with Braswell family processors, the processor does not expose its temperature to external components -- including the Super I/O IC that is responsible for making fan speed control decisions. Instead, an inference for the processor's temperature is made based upon the temperature of the components responsible for regulating the processor's voltage. The fan is controlled based upon this inference.
So, what is the problem? Are you seeing concerning processor temperatures? Let me put things in perspective: If the processor, when under load, is staying below ~80°C, then you do not need to be at all concerned. These processors could stay at this temperature for their entire warranted lifetime and will never suffer any thermal degradation (damage) as a result...
Hope this helps,