Hi Michael, I can reproduce this bug on Strech as well (systemd-sysv 232-25+deb9u1).
I think you should however also fix this bug on Jessie, because it is a recent regression (was not present on Jessie 8.6). Based on the package's recent changelog, it may be a regression of "systemctl: Fix argument handling when invoked as shutdown. (Closes: #776997)" introduced on 215-17+deb8u6 (it's just a guess, but it is the only recent fix on shutdown's argument handling). Regards Thomas
