Description of problem:
During the last two dnf updates, I started seeing this:
Upgrading : selinux-policy-3.13.1-219.fc25.noarch 15/230
libsemanage.add_user: user system_u not in password file
So either system_u user creation failed for some reason (and should be fixed), or it is a harmless warning, and in that case, can you please not print it? Only real errors should be printed, anything else will just clutter the output and make people overlook the real errors.
Version-Release number of selected component (if applicable):
Thanks for the report.
It's a harmless warning and system_u will be removed from SELinux users in the next update.
*** This bug has been marked as a duplicate of bug 1378204 ***