ROW_NUMBER differs from the number in the error message upon ER_WARN_DATA_OUT_OF_RANGE

CREATE OR REPLACE TABLE t (a INT);

INSERT INTO t VALUES (1),(2);

SELECT CAST(a AS DECIMAL(2,2)) AS f FROM t;

get diagnostics condition 2 @n = row_number, @m = message_text;

select @n, @m;

+------+--------------------------------------------+

| @n   | @m                                         |

+------+--------------------------------------------+

|    2 | Out of range value for column 'f' at row 1 |

+------+--------------------------------------------+

1 row in set (0.000 sec)

MariaDB [test]> show warnings;

+---------+------+--------------------------------------------+

| Level   | Code | Message                                    |

+---------+------+--------------------------------------------+

| Warning | 1264 | Out of range value for column 'f' at row 1 |

| Warning | 1264 | Out of range value for column 'f' at row 1 |

+---------+------+--------------------------------------------+

2 rows in set (0.000 sec)