Upgrade to Satellite 6.5 fails at 'Validate availability of repositories'

Issue

1) When attempting to upgrade Satellite from 6.4 to 6.5, the following error is encountered:

--------------------------------------------------------------------------------
Validate availability of repositories:
/ Some repositories missing, calling `subscription-manager refresh`   [FAIL]
Following repositories are not available on your system: rhel-server-7-satellite-6-beta-rpms
--------------------------------------------------------------------------------

• No beta repository should be required.

2) No such sub-command:

[root@satellite6.4 ~]# foreman-maintain advanced procedure run maintenance-mode-enable
ERROR: No such sub-command 'maintenance-mode-enable'