plugins.server_audit fails sporadically in buildbot

Random failure (Fails on some buildbots, not on all and not on my development machine)

http://buildbot.askmonty.org/buildbot/builders/kvm-deb-xenial-x86/builds/14935/steps/mtr/logs/stdio

plugins.server_audit w2 [ fail ]
Test ended at 2020-01-29 18:23:36

CURRENT_TEST: plugins.server_audit
— /usr/share/mysql/mysql-test/suite/plugins/r/server_audit.result 2020-01-29 16:27:10.000000000 -0500
+++ /dev/shm/var/2/log/server_audit.reject 2020-01-29 18:23:36.122575174 -0500
@@ -439,6 +439,7 @@
TIME,HOSTNAME,root,localhost,ID,ID,QUERY,sa_db,'set global server_audit_file_path=\'nonexisting_dir/\'',0
TIME,HOSTNAME,root,localhost,ID,ID,QUERY,sa_db,'SHOW WARNINGS',0
TIME,HOSTNAME,root,localhost,ID,ID,QUERY,sa_db,'show status like \'server_audit_current_log\'',0
+TIME,HOSTNAME,user1,localhost,ID,0,DISCONNECT,sa_db,,0
TIME,HOSTNAME,root,localhost,ID,ID,QUERY,sa_db,'show variables like \'server_audit%\'',0
TIME,HOSTNAME,root,localhost,ID,ID,WRITE,mysql,plugin,
TIME,HOSTNAME,root,localhost,ID,ID,QUERY,sa_db,'uninstall plugin server_audit',0