For a schema like example2.ldif and a configuration like:
testLdapExample22 {
org.jboss.security.auth.spi.LdapExtLoginModule
java.naming.factory.initial=com.sun.jndi.ldap.LdapCtxFactory
java.naming.provider.url="ldap://lamia/"
java.naming.security.authentication=simple
bindDN="cn=Root,dc=jboss,dc=org"
bindCredential=secret1
baseCtxDN="ou=People,o=example2,dc=jboss,dc=org"
baseFilter="(uid=

{0})"
rolesCtxDN="ou=Roles,o=example2,dc=jboss,dc=org";
roleFilter="(uid={0}

)"
roleAttributeID="memberOf"
roleAttributeIsDN="true"
roleNameAttributeID="cn"
roleRecursion=0
};

Only one role is being pulled from the cn=EchoGroup,ou=Roles,o=example2,dc=jboss,dc=org context, rather the both EchoGroup and TheDuke as only one of the cn attribute values is retrieved.