I think it should be around 0.7-0.8V idle. May be there was but I hide the sensors I don't use and it's not under the hidden sensors now. This Vcore showed exactly what my BIOS for CPU voltage, that's why I kept it.
Yes under load shows the correct value 1.05V
You cannot compare the BIOS Vcore value with one in Windows, as the system conditions are very different (unless fixed voltage is used).
On some systems (Haswell-based especially) Vcore monitoring doesn't work properly, so lots of vendors rather report the VID instead of Vcore. This might be your case as well. Can you please compare the Vcore/VID values shown by HWiNFO side-by-side with GIGABYTE's tool ?
Sorry, but what means "so far"? What changed when you noticed it's not correct - a new HWiNFO version, or something in your system? There were no changes in HWiNFO in this matter.
In the last screenshot you posted it shows a minimum value of 0.048 V which doesn't seem correct either.
I suspected it's because of the beta version but it looks like because I set the CPU voltage to "Auto" instead the usual undervolt (-20 mV). Is it something that can be fixed or I should use the VID sensors instead and hide this ?
HWiNFO reports straight the sensor value which should represent Vcore, so there's nothing I can do about it.
Unfortunately on Haswell-based system Vcore monitoring it tricky because of the Fully Integrated Voltage Regulator (FIVR), so it might be better to rely on VID instead.