UI: warning "Connection to ... closed by remote host." injects into log during reboots

[danbst]

When redeploying Hetzner machine, message "Connection to MY_IP closed by remote host." injects into output log. This was frightening at first, because initial deploy had no such

hetznerIron> installing machine...
hetznerIron> rebooting machine в??hetznerIronв?T (MY_IP) into rescue system
hetznerIron> sending reboot command... done.
hetznerIron> waiting for rescue system...Connection to MY_IP closed by remote host.
[down]..............................................................[up]

Looks like, first ever Hetzner reboot is done via Robot API, the consequent reboots are done with systemctl reboot. Those, which are done via systemctl reboot are producing the above warning.