Hi,
i had both issues. The power cable that is faulty and causes short power cuts (the kemper freeze). The USB key that makes the Kemper Stage freeze again.
Now i've been able to update the firmware with the Rig Manager, i changed the power cable and the Kemper stops after about 20 minutes while profiling.
I have to unplug it during 15 minutes then it starts again.
Any ideas?