AMD Threadripper BIOS Reporting Wrong Temps?

[InvalidError]

I love the readings but doubt whether their accurate (but it would be great if they were).

Even with the most absurd closed liquid cooling loop, it is impossible to get temperatures lower than ambient on its own. Just the silicon wafer's thickness guarantees a ~10C difference between the junction temperature and package under full load. If the temperature circuit worked correctly, you should be seeing core temperatures at least 10C above ambient.