It could just be the software itself.
When I see posts such as this that fail to recognise that three different 3rd party utilities all report the same information I feel they are ill considered. If it was just SIV then OK, but all three reporting the same incorrect information is unlikely unless there is a hardware issue.
I feel it would be far more helpful to go302lx if you checked what SIV reported for your Gigabyte X99-UD4P-CF system as that also uses the ITE IT8620E sensor chip. I suspect that no unexpected values will be reported as was the case in the attached. Note that you need to close down the Gigabyte utility before running 3rd party utilities as unlike HWM + HWiNFO +SIV it fails to use
mutexes to interlock access to the motherboard sensors. I suspect in the past you failed to do this which is why things "went crazy".
It's also worth mentioning that only the readings from the ITE IT8620 are wonky and the ITE IT8733 readings are as expected.
Further the Gigabyte X99M-Gaming 5 has identical sensor chips to the Gigabyte X99-Designare EX-CF and below you can see SIV reports sensible information for the Gaming 5.
It would be good to know what happens with other Gigabyte X99-Designare EX-CF systems.
