Postgres role does not exist but shows up in du

I have a role in postgres which i want to drop. But unable to do so. seems some metadata is missing ?

=# \du
                                                 List of roles
    Role name     |                         Attributes                         |           Member of
------------------+------------------------------------------------------------+-------------------------------
 postgres         | Superuser, Create role, Create DB, Replication, Bypass RLS | {}
 rafm_adm         |                                                            | {}
 rafm_adm_S       | Cannot login                                               | {}
 rafm_adm_SIUD    | Cannot login                                               | {}

rafm_adm is the role. When i try dropping or reassign owner, I get the error that it doesn't exist.

# drop role rafm_adm_S ;
ERROR:  role "rafm_adm_s" does not exist

Can someone help ?