Still an issue. It seems to occur after a couple of priv user logins - and I see abrt-cli fail as well. This impacts:
Files in /etc/ directory
/etc/shadow has all permissions removed (this is exhibited while remote logged in and locally login/logout.)
Files in /usr/share
.* files in user directories /home/<user>
In all cases, systemd-bus-proxy takes ownership of files that are root, application, or user owned. I have not been able to determine why it discriminates some files over others (ie not all files get corrupted).