Incorrect data size in CREATE TABLE when using JSON_INSERT in a subquery

CREATE TABLE src(val LONGTEXT);

INSERT INTO src VALUES(REPEAT('x',100));

CREATE TABLE t2 AS

  SELECT JSON_INSERT('{"k1":"v1"}', '$.k3', val) AS j

  FROM src

  LIMIT 0;

SHOW CREATE TABLE t2;

-- t2	CREATE TABLE `t2` (

--   `j` varchar(36) DEFAULT NULL

-- ) ENGINE=InnoDB DEFAULT CHARSET=utf8mb4 COLLATE=utf8mb4_uca1400_ai_ci

-- This is incorrect as the size of j is only 36, 122 is expected 

INSERT IGNORE INTO t2

  SELECT JSON_INSERT('{"k1":"v1"}', '$.k3', val) AS j

  FROM src;

-- Warning	1265	Data truncated for column 'j' at row 1