`mosh-server` should be added to the list of processes which should be exempt from this behaviour, as it is based on the principle of "ssh into remote host, start daemon, exit ssh, continue speaking to daemon".
As a workaround, I'm running it in a new session explicitly: mosh --server "systemd-run --scope --user mosh-server" $hostname To make this more googlable, the error message which happens when systemd kills mosh-server is: mosh: Nothing received from server on UDP port 60001. [To quit: Ctrl-^ .]
