`DISTINCT` + `char_length(SPACE(AVG(…)))` + `HAVING` returns empty for one insertion order of the same rows

CREATE TABLE t (

  c_pk BIGINT NOT NULL, c_int BIGINT, c_big BIGINT, c_dec DECIMAL(10,2),

  c_dbl DOUBLE, c_txt VARCHAR(255), c_chr VARCHAR(255), c_date DATE, c_ts DATETIME(6)

);

-- Even pks first (view2), then odd pks (view23). Expected 2 rows. Actual 0 rows.

INSERT INTO t VALUES (2, -7, 2, 999.99, 1000.125, 'trailing ', 'o''brien', '1999-12-31', '2024-01-15 12:34:56');

INSERT INTO t VALUES (4, 2, -1, 12.34, 1.5, 'abc', NULL, '1999-12-31', '1999-12-31 23:59:59');

INSERT INTO t VALUES (6, 0, 0, -5.50, NULL, 'o''brien', 'trailing ', '1999-12-31', '1999-12-31 23:59:59');

INSERT INTO t VALUES (8, -7, 2, 999.99, 1000.125, 'trailing ', 'o''brien', '1999-12-31', '2024-01-15 12:34:56');

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

INSERT INTO t VALUES (3, 2, -1, NULL, 1000.125, 'o''brien', '', '1999-12-31', '1999-12-31 23:59:59');

INSERT INTO t VALUES (5, 42, NULL, 0.00, NULL, '', 'trailing ', '2030-06-01', '2024-01-15 12:34:56');

INSERT INTO t VALUES (7, NULL, 2, -5.50, -1.5, 'abc', NULL, '2024-01-15', '1999-12-31 23:59:59');

SELECT DISTINCT t1.c_int,

       char_length(SPACE(AVG(CAST(t1.c_int AS SIGNED))))

FROM t t1

WHERE t1.c_int IS NOT NULL

GROUP BY t1.c_int, t1.c_ts, t1.c_dec, t1.c_big, t1.c_dbl

HAVING AVG(t1.c_big) <= t1.c_int;

-- Expected 2 rows (0,0), (2,2). Actual 0 rows.

-- Same rows, odd-then-even INSERT order (control: CORRECT).

CREATE TABLE t (

  c_pk BIGINT NOT NULL, c_int BIGINT, c_big BIGINT, c_dec DECIMAL(10,2),

  c_dbl DOUBLE, c_txt VARCHAR(255), c_chr VARCHAR(255), c_date DATE, c_ts DATETIME(6)

);

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

INSERT INTO t VALUES (3, 2, -1, NULL, 1000.125, 'o''brien', '', '1999-12-31', '1999-12-31 23:59:59');

INSERT INTO t VALUES (5, 42, NULL, 0.00, NULL, '', 'trailing ', '2030-06-01', '2024-01-15 12:34:56');

INSERT INTO t VALUES (7, NULL, 2, -5.50, -1.5, 'abc', NULL, '2024-01-15', '1999-12-31 23:59:59');

INSERT INTO t VALUES (2, -7, 2, 999.99, 1000.125, 'trailing ', 'o''brien', '1999-12-31', '2024-01-15 12:34:56');

INSERT INTO t VALUES (4, 2, -1, 12.34, 1.5, 'abc', NULL, '1999-12-31', '1999-12-31 23:59:59');

INSERT INTO t VALUES (6, 0, 0, -5.50, NULL, 'o''brien', 'trailing ', '1999-12-31', '1999-12-31 23:59:59');

INSERT INTO t VALUES (8, -7, 2, 999.99, 1000.125, 'trailing ', 'o''brien', '1999-12-31', '2024-01-15 12:34:56');

SELECT DISTINCT t1.c_int,

       char_length(SPACE(AVG(CAST(t1.c_int AS SIGNED))))

FROM t t1

WHERE t1.c_int IS NOT NULL

GROUP BY t1.c_int, t1.c_ts, t1.c_dec, t1.c_big, t1.c_dbl

HAVING AVG(t1.c_big) <= t1.c_int;

-- 2 rows (0,0), (2,2)  ✓