First, you are reading number off different sensors. There is a sensor located at the center (geometric center) of the Integrated heat sink. The thermal reading off that particular sensor is called Tcase. The thermal readings you get off each individual core are called Tjunction. Usually, The difference between Tcase and Tjunction should be very close unless it is under load, which will then be about 15 degree apart(the difference is called delta between Tcase and Tjunction). Tcase usually has lower readings then Tjunction as Tjunction is closer to the source of heat. BIOS reads off TCase, while the numbers you have shown are all TJunction. Dig into those settings to show TCase. There are no offset you can play with in BIOS on TCase. If it is a firmware problem, then you won't be the first person who run into this.
Cut those crap and back to your problem. It appears the Tcase of your CPU is too high while Tjunction reminds low. This is not usual because the temp off the source of heat can not be lower than reading off the geometric center of the IHS. While Zap's point is still valid as if the center of the IHS isn't touching the HS, it is possible for it to have a higher reading. If the IHS or HS both concaved in then it is possible. That is what thermal paste is for.
People even say too much thermal is bad, but what they really mean is the performance of thermal conductivity of the paste decreases if you put too much, but how much is too much? If the 2 surface are flat, then a grain of rice worth of thermal is enough, but that requires the assembler put the pasting at the center of the ISH and spread those pasting evenly by turning the HS on top of IHS slightly, about 5-10 degree in both directions until it the pasting is spread out evenly before locking the HS in place. If the assembler move the HS in a circler motion instead of rotating the HS and the surfaces are concaved in, then there is a small chance that this will happen. I say you have a defective CPU where the TCase sensor isn't working properly.
Edit: for the fun of it, you can see if the surface is flat by placing a blade on top of it (blade that is used it cutters.)