how much sequcence can a postgresql id column could using

when I am using this command to get the sequence of my table in PostgreSQL 13:

select pg_get_serial_sequence('public.rss_sub_source', 'id')

shows that current sequence is public.rss_sub_source_id_seq. then I am using this command to query the relation of table sequence:

SELECT t.oid::regclass AS table_name,
       a.attname AS column_name,
       s.relname AS sequence_name
FROM pg_class AS t
   JOIN pg_attribute AS a
      ON a.attrelid = t.oid
   JOIN pg_depend AS d
      ON d.refobjid = t.oid
         AND d.refobjsubid = a.attnum
   JOIN pg_class AS s
      ON s.oid = d.objid
WHERE --d.classid = 'pg_catalog.pg_class'::regclass
  --AND d.refclassid = 'pg_catalog.pg_class'::regclass
   d.deptype = 'i'
  AND t.relkind IN ('r', 'P')
  AND s.relkind = 'S';

shows that the sequence is rss_sub_source_id_seq1? why id column has two sequence? which one is using? how to avoid this situation? is it a PostgreSQL 13 bug?