Comment 8 for bug 1484027

Addl comment which could be considered by a future fix...

The point and the issue of the problem in fact should address is the following - given the tmpfiles.d behaviour as follows in man -S5 tmpfiles.d:
...
Files in /etc/tmpfiles.d override files with the same name in /usr/lib/tmpfiles.
and /run/tmpfiles.d. Files in /run/tmpfiles.d override files with the same name in
/usr/lib/tmpfiles.d. Packages should install their configuration files in
/usr/lib/tmpfiles.d. Files in /etc/tmpfiles.d are reserved for the local administrator,
who may use this logic to override the configuration files installed by vendor
packages. All configuration files are sorted by their filename in lexicographic order,
regardless of which of the directories they reside in. If multiple files specify the same
path, the entry in the file with the lexicographically earliest name will be applied. All
other conflicting entries will be logged as errors.
...

Considering this, the /usr/lib/tmpfiles.d/00rsyslog.conf file in line 6 (delivered by rsyslog 8.16.0-1ubuntu3 package) to my perception is derived as effective line for /var/log, the /usr/lib/tmpfiles.d/var.conf file line 14 delivered by systemd
in the 229-4ubuntu10 package will cause the logging. Since that is an out-of-the-box setting,
there should be a discussion of the topic with decision to be taken among systemd and rsyslogd that ONE of the two parties is delivering a tmpfiles config only.