Inconsistent use of casting syntax in routines

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WITH routines_with_casting AS (SELECT 
  n.nspname AS routine_schema, 
  pr.proname AS routine_name, 
   pg_get_function_identity_arguments(pr.oid) AS parameters,
   pg_get_functiondef(pr.oid) AS routine_src_original,
  regexp_replace(pg_get_functiondef(pr.oid),'[\r\n]','<br>','g')  AS routine_src,  
  CASE WHEN pr.prokind='f' THEN 'FUNCTION'
  WHEN pr.prokind='p' THEN 'PROCEDURE'
  WHEN pr.prokind='w' THEN 'WINDOW FUNCTION' END AS routine_type,
  l.lanname AS routine_language
FROM 
  pg_catalog.pg_proc pr, 
  pg_catalog.pg_namespace n,
  pg_catalog.pg_language l
WHERE 
  pr.pronamespace = n.oid 
  AND pr.prolang=l.oid 
  AND pr.prokind<>'a'  
  AND pg_get_functiondef(pr.oid)~*'(\:\:|cast[(])'
  AND pr.proname NOT IN ('f_assume_you_must_use_files', 'f_check_format_comma_separated_list', 'f_check_password', 'f_default_value_with_no_match') 
  AND NOT EXISTS (SELECT 1
FROM pg_catalog.pg_depend d 
WHERE EXISTS (SELECT 1 
FROM pg_catalog.pg_extension e 
WHERE d.refobjid=e.oid) AND
d.objid=pr.oid)
AND n.nspname NOT IN (SELECT schema_name
FROM INFORMATION_SCHEMA.schemata
WHERE schema_name<>'public' AND
schema_owner='postgres' AND schema_name IS NOT NULL))
SELECT routine_schema, routine_name, parameters, routine_src, routine_type, routine_language
FROM routines_with_casting
WHERE EXISTS (SELECT * FROM routines_with_casting WHERE routine_src_original~*'\:\:')
AND EXISTS (SELECT * FROM routines_with_casting WHERE routine_src_original~*'cast[(]')
ORDER BY routine_schema, routine_name, parameters;