wsrep_info.plugin fails sporadically in buildbot

wsrep_info.plugin 'innodb_plugin'        w3 [ fail ]  Found warnings/errors in server log file!

        Test ended at 2016-12-09 09:21:06

line

2016-12-09  9:21:01 70366340837632 [Warning] WSREP: SYNC message from member 0 in non-primary configuration. Ignored.

^ Found warnings in /dev/shm/var/3/log/mysqld.1.err

ok

line

2016-12-09  9:21:01 70366152093952 [Warning] WSREP: SYNC message from member 0 in non-primary configuration. Ignored.

^ Found warnings in /dev/shm/var/3/log/mysqld.2.err

ok