This is what the GPU reports, and it's not just the 8-pin, but all other +12V rails. I don't know if it's a bug there, with such low voltages the GPU would probably not be able to run properly.
You might confirm with GPU-Z what that shows.
Thanks, must be an uncalibrated sensor on tbe GPU. I was able to get a working digital multimeter and I am getting a read out that is 0.1V close to what HWinfo64 is reporting on 12v whicj is 11.98V to 12.1V