This is reproducible everytime. Doing a CREATE from SELECT, and then adding INDEX on column results in crashing of all other servers in Galera cluster.
I have attached my.cnf MariaDB configuration, and the test setup is simple consiting of three servers. Execute this on one of the servers:
And all the rest of the servers will crash. I have attached relevant log files. Take a look at server.2.log or server.3.log.
Some widely used software (ie Drupal's Views Data Export module) uses this statements, which is how we encountered this bug.