SHOW CREATE FUNCTION generates syntax error

MariaDB [idm]> SHOW CREATE FUNCTION `calculate_real_timestamp`;

ERROR 1064 (42000): You have an error in your SQL syntax; check the manual that corresponds to your MariaDB server version for the right syntax to use near 'offset int(11), timezone int(11)) RETURNS decimal(20,4)

    DETERMINISTIC

BEG...' at line 1

ERROR 1064 (42000): You have an error in your SQL syntax; check the manual that corresponds to your MariaDB server version for the right syntax to use near 'offset int(11), timezone int(11)) RETURNS decimal(20,4)

    DETERMINISTIC

BEG...' at line 1

MariaDB [idm]> select * FROM information_schema.routines where routine_name='calculate_real_timestamp'\G

*************************** 1. row ***************************

           SPECIFIC_NAME: calculate_real_timestamp

         ROUTINE_CATALOG: def

          ROUTINE_SCHEMA: app

            ROUTINE_NAME: calculate_real_timestamp

            ROUTINE_TYPE: FUNCTION

               DATA_TYPE: decimal

CHARACTER_MAXIMUM_LENGTH: NULL

  CHARACTER_OCTET_LENGTH: NULL

       NUMERIC_PRECISION: 20

           NUMERIC_SCALE: 4

      DATETIME_PRECISION: NULL

      CHARACTER_SET_NAME: NULL

          COLLATION_NAME: NULL

          DTD_IDENTIFIER: decimal(20,4)

            ROUTINE_BODY: SQL

      ROUTINE_DEFINITION: BEGIN

RETURN (time / 1000000) + ((ABS(offset) > 43200) * offset) + ((ABS(offset) < 1800) * ((timezone * 60) + 0)) + ((ABS(offset) > 43200) * ((timezone * 60) + 0));

END

           EXTERNAL_NAME: NULL

       EXTERNAL_LANGUAGE: NULL

         PARAMETER_STYLE: SQL

        IS_DETERMINISTIC: YES

         SQL_DATA_ACCESS: CONTAINS SQL

                SQL_PATH: NULL

           SECURITY_TYPE: DEFINER

                 CREATED: 2022-03-28 22:22:55

            LAST_ALTERED: 2022-03-28 22:22:55

                SQL_MODE: 

         ROUTINE_COMMENT: 

                 DEFINER: root@localhost

    CHARACTER_SET_CLIENT: utf8

    COLLATION_CONNECTION: utf8_general_ci

      DATABASE_COLLATION: latin1_swedish_ci

1 row in set (0,016 sec)