PCH disappears after sleep


As per title, PCH disappears after a sleep/resume, and it does not come back unless a there is a reboot (ie logging out/in does not fix it). Windows 10 Pro HWinfo v 5.84.3450
Which PCH values is that, the Intel PCH sensor with a single "PCH Temperature" value?
If it doesn't come up when you restart HWiNFO, then it looks like a BIOS bug.
What is the relationship between the BIOS and the PCH ? How do you read the PCH temperature sensor, and what can the BIOS do to stop you? I am asking out of sheer curiosity because my PCH is very hot (reaches 100C) and would like to know and to understand more.