mariabackup.innodb_redo_overwrite failed in buidbot with result length mismatch

mariabackup.innodb_redo_overwrite 'innodb' w3 [ fail ]

        Test ended at 2020-10-23 14:01:18

CURRENT_TEST: mariabackup.innodb_redo_overwrite

--- /usr/share/mysql-test/suite/mariabackup/innodb_redo_overwrite.result	2020-10-23 09:25:11.000000000 +0000

+++ /dev/shm/var/3/log/innodb_redo_overwrite.reject	2020-10-23 14:01:18.382601733 +0000

@@ -22,7 +22,7 @@

 INSERT INTO t SELECT * FROM t;

 INSERT INTO t SELECT * FROM t;

 # xtrabackup backup

-FOUND 1 /failed: redo log block is overwritten/ in backup.log

+NOT FOUND /failed: redo log block is overwritten/ in backup.log

 FOUND 1 /failed: redo log block checksum does not match/ in backup.log

 FOUND 1 /failed: unknown reason/ in backup.log

 DROP TABLE t;

mysqltest: Result length mismatch