Incorrect result of JSON_OBJECT_FILTER_KEYS

CREATE TABLE t(doc JSON, keys_json JSON);

INSERT INTO t VALUES

  ('{"a":1,"b":2}', '["a"]'),

  ('{"a":1,"b":2}', '["b"]');

SELECT JSON_OBJECT_FILTER_KEYS('{"a":1,"b":2}', '["a"]'); -- {"a": 1}

SELECT JSON_OBJECT_FILTER_KEYS('{"a":1,"b":2}', '["b"]'); -- {"b": 2}

SELECT keys_json, JSON_OBJECT_FILTER_KEYS(doc, keys_json) AS filtered

FROM t ORDER BY keys_json; -- ["a"]   NULL, ["b"]   NULL