Temporary MyISAM table is marked as crashed after re-opening

CREATE TEMPORARY TABLE t1 (f VARCHAR(8)) ENGINE=MyISAM;

INSERT INTO t1 () VALUES (),(),(),();

INSERT INTO t1 SELECT * FROM t1;

DELETE FROM t1 LIMIT 1;

OPTIMIZE TABLE t1;

INSERT INTO t1 SELECT * FROM t1;

INSERT INTO t1 SELECT * FROM t1;

OPTIMIZE TABLE t1;

Table	Op	Msg_type	Msg_text

test.t1	optimize	status	OK

INSERT INTO t1 SELECT * FROM t1;

INSERT INTO t1 SELECT * FROM t1;

bug.crashed3                             [ fail ]

        Test ended at 2018-12-01 00:35:53

CURRENT_TEST: bug.crashed3

mysqltest: At line 7: query 'INSERT INTO t1 SELECT * FROM t1' failed: 1194: Table 't1' is marked as crashed and should be repaired