Comment # 1 on bug 1223617 from Radoslav Kolev

Hello!

Where does the file /etc/tmpfiles.d/var.conf come from?

Can you share its contents?

It is expected to get the duplicate warning in the log if multiple files
specify the same path. See CONFIGURATION DIRECTORIES AND PRECEDENCE section of
'man tmpfiles.d'.

If you want to override some settings from a system supplied file found under  
/usr/lib/tmpfiles.d/ then you have to create a file with the same name under
/etc/tmpfiles.d/ and in this way the on under /usr/lib/tmpfiles.d/ will be
ignored.