Fwiw, looking at https://pastebin.canonical.com/45915/ it looks like the shutdown script is targeting "/usr/bin/python2.6 -S bin/run -i production-mailman" for shutdown rather than "/usr/bin/python2.6 ./mailmanctl -s start". I'm not sure if this is correct or not, but it explains why the mailmanctl process is still around after a shutdown.
Fwiw, looking at https:/ /pastebin. canonical. com/45915/ it looks like the shutdown script is targeting "/usr/bin/python2.6 -S bin/run -i production-mailman" for shutdown rather than "/usr/bin/python2.6 ./mailmanctl -s start". I'm not sure if this is correct or not, but it explains why the mailmanctl process is still around after a shutdown.