Tried with FreeNAS-8.0-RC2-amd64, FreeNAS-8.0-RC3-amd64, FreeNAS-8.0-RC4-amd64, and FreeNAS-8.0-RC5-amd64.
Logged in as root over ssh with the default password (freenas).
Changed the root password via the passwd command.
Logged out.
Attempted to log back in as root using the default password and it fails as expected.
Attempted to log back in as root using the new password and it succeeds as expected.
Rebooted.
Attempted to log back in as root using the new password but it unexpectedly failed.
Attempted to log back in as root using the default password and it unexpectedly succeeded.
"For 8.x, use http://support.freenas.org"
Re-filed at https://support.freenas.org/ticket/297.
All future commentary should be done at the above URL instead of on this bug ID: 3286981.