Increasing the lock wait timeout in mariadb/galera resolved the issue.

MariaDB [(none)]> set innodb_lock_wait_timeout=100;
Query OK, 0 rows affected (0.00 sec)
MariaDB [(none)]> show variables like 'innodb_lock_wait_timeout';
-------------------------------+
Variable_name	Value
-------------------------------+
innodb_lock_wait_timeout	 100
-------------------------------+
1 row in set (0.00 sec)
MariaDB [(none)]> quit
Bye

Closing this as NOTABUG. A valid workaround was provided in comment #6.