Okay so what is going on here.?
Wnenever running the fan tuning algorithm in FanXpert, the Power Limit Throttling bit inside the Intel XTU is getting activated:

The limiting gets activated the moment the fan tuning algorithm starts - and is deactivated the moment the algorithm finishes. It's reproducible, and continues to occur after a reboot. And it doesn't feel like a false indication -the system is obviously responding slowly while the fan training algorithm operates.
As you can see from the other figures visible inside the XTU monitoring panel, there is no undue power draw at all - let alone enough to trip the limit.
What's going on here? Is this a bug? Or is the training algorithm *deliberately * causing a false trigger of the power limit to lock the processor in a low power configuration to avoid any accidental overheats while the fans are stopped?