Failed to INSERT a proper value when no FOREIGN KEY violation

CREATE TABLE t0 (c2 FLOAT8, PRIMARY KEY (c2));

CREATE TABLE t1 (c1 FLOAT8 UNIQUE, FOREIGN KEY (c1) REFERENCES t0(c2) ON UPDATE CASCADE);

ALTER TABLE t0 RENAME AS t2, ALGORITHM COPY;

INSERT INTO t2 (c2) VALUES (1);

INSERT INTO t1 (c1) VALUES (1); -- actual: failed, expected: succeed

ERROR 1452 (23000): Cannot add or update a child row: a foreign key constraint fails (`test`.`t1`, CONSTRAINT `t1_ibfk_1` FOREIGN KEY (`c1`) REFERENCES `t0` (`c2`) ON UPDATE CASCADE)