kernel_taskCPU Usage is due to high chassis temperature caused by charging. In particular Left Thunderbolt port usage.
- Move charging from the left to the right side. If you have a second charger then plug it in on the right side. Avoid plugging everything on the right side (see last paragraph below).
- Unplug something from the left side. Either power or another accessory until the battery is full.
- Force fans to max before plugging in. iStatMenus has an easy Sensors -> Fans menu item to do so. This only helps in marginal conditions.
- Move to a cooler room.
Just so happens that my set-up is such that I can only charge using the right side TB3 port, now let’s move on to finding the next obscure solution to the next MacbookPro issue.