[ERROR] InnoDB: Unlock row could not find a 2 mode lock on the record

This is MariaDB's variant of https://bugs.mysql.com/bug.php?id=76803 .

If there is an outer join with a constant inner table, a locking-read statement (UPDATE or SELECT... FOR UPDATE) will produce these kind of warnings in the error log:

[ERROR] InnoDB: Unlock row could not find a 3 mode lock on the record. Current

statement: SELECT * FROM t1 LEFT JOIN t2 ON t1.c2=t2.c2 AND t2.c1=1 FOR UPDATE