'kill ' gives ERROR 1095 (HY000): You are not owner of thread ... even though I am
The error message is misleading. Galera can mark user threads as high priority which means they can't be killed. Currently, this gives the ERROR 1095 (HY000): You are not owner of thread... See MDEV-12008 for details.

This will probably affect other distributions of Galera as well, such as Percona XtraDB Cluster.