HB9TMC

Could it be that the kiwis IP adress changes after it was switched off?

That sounds like a power supply issue, I've never seen unexpected reboots.

Maybe you can see using journalctl whether it was a clean shutdown, in that case there would be something like this:

Dec 15 11:27:44 kiwi systemd[1]: Reached target Shutdown.
Dec 15 11:27:44 kiwi systemd[1]: Reached target Final Step.
Dec 15 11:27:44 kiwi systemd[1]: systemd-reboot.service: Succeeded.
Dec 15 11:27:44 kiwi systemd[1]: Finished Reboot.
Dec 15 11:27:44 kiwi systemd[1]: Reached target Reboot.
Dec 15 11:27:44 kiwi systemd[1]: Shutting down.

Another possibility would be that the kiwi's power supply has a Class-Y capacitor that leaks common-mode voltage to the DC side, which is then coupled trough the loop to ground.

In that case you could measure an AC voltage between the Kiwi GND and PE.

They do look like pileups, I think there are some dxpeditions. C21MM and PX0FF.

You could check the other voltages:

http://kiwisdr.com/ks/troubleshooting.pdf