Incorrect result of $[last] of JSON

CREATE TABLE t(

  id INT PRIMARY KEY,

  j JSON

);

INSERT INTO t VALUES

  (1, '["x","target"]'),

  (2, '["x","y","target"]');

SELECT id,

       JSON_EXTRACT(j, '$[last]') AS extracted_last,

       JSON_SEARCH(j, 'one', 'target', NULL, '$[last]') AS searched_last

FROM t

ORDER BY id;

-- 1	"target"	"$[1]"

-- 2	"y"	NULL