Hello,
I've been bitten by this, beware of it: https://bugs.debian.org/cgi-bin/bugreport.cgi?bug=902185 (https://bugs.debian.org/cgi-bin/bugreport.cgi?bug=902185)
Also, a workaround in the bug report.
Cheers
[edit by musca: solved with systemd 239-2]
When I saw that failure to install, I ran
apt -f install
then a reboot and everything works correctly (2 systems).