CSIT Sporadic failures - floating IP unreachable

two instances are assigned a floating ip and connectivity is tested with a
ping from the control node. In this CSIT failure, one of the floating
ips is not reachable. The other is responding.

possibly digging in to the flow dumps will point to something wrong?
I checked that the floating ip addresses for specific flows looked
the same for the working and non-working floating ips, but that's as
far as I went.

https://logs.opendaylight.org/releng/jenkins092/netvirt-csit-1node-openstack-mitaka-upstream-learn-carbon/192/archives/log.html.gz