Amending #16: as indicated by #10, disabling gpe01 indeed brings kapcid down to a normal CPU usage, even if gpe01 is still reported as enabled. So the work-around from korg works also in my case.
Amending #16: as indicated by #10, disabling gpe01 indeed brings kapcid down to a normal CPU usage, even if gpe01 is still reported as enabled. So the work-around from korg works also in my case.