ORA-62569: nested polymorphic table function is disallowed

create or replace package tq84_ptf_pkg authid definer as

   function describe(tab in out dbms_tf.table_t) return dbms_tf.describe_t;
end tq84_ptf_pkg;
/

create or replace package body tq84_ptf_pkg as

   function describe(tab in out dbms_tf.table_t) return dbms_tf.describe_t
   is begin
      return null;
   end describe;

end tq84_ptf_pkg;
/


create or replace function tq84_ptf(tab table) return table pipelined row polymorphic using tq84_ptf_pkg;
/

select * from tq84_ptf(dual);

select * from tq84_ptf(tq84_ptf(dual));

with a as (select * from tq84_ptf(dual))
select * from tq84_ptf(a);