That in the failover cluster manager under roles it should be listed. Is this true?
Not under the roles, because listener is not a role but a resource as per WSFC. It would be listed in resource tab of AG name.
If it is true what would cause the listener not to show up as a cluster resource if it is configured. The listener name does work.
It should ideally. Did you check at right place. For my 2 node AG it shows as below