--pipe, -P
If specified, standard input, output, and error of the transient service are inherited from the systemd-run command itself. This allows systemd-run to be used within shell pipelines. Note that this mode is not suitable for interactive command shells and similar, as the service process will not become a TTY controller when invoked on a terminal. Use --pty instead in that case.
А у тебя в команде и --pty и --pipe указаны вместе.