Hi Greg,
We suggest comparing the readings when the Surface Pro is docked and when it's not. It will help us point out if the Surface Dock causes the unusual behavior when docking or connecting your Surface pro to it. As suggested on your other post, please check if the firmware for the Surface Dock is updated. Here's your reference in updating the Surface Dock.
If you don't see any changes after updating the Surface Dock and it gives the same results when monitoring the CPU usage on the device, please take the time to drop by a Microsoft Store to have the devices checked.
Come back if you need more help.
Regards.