[system test] Cannot add back just rebalanced out node - Error " node is already part of cluster"

1. Rebalance out 1 index node - success
2. Rebalance In same index node - fails with error
Prepare Join failed. Node is already part of the cluster.

3. Stopped/Started couchbase service on the cluster,
iptables -F ... Node add back does not work.

Attention - Prepare join failed. Could not connect to "172.23.107.183" on port 8091. This could be due to an incorrect host/port combination or a firewall in place between the servers.

I ve seen the above twice on rebalance out/in of 2 different nodes.

Logs

https://s3.amazonaws.com/cb-customers/rebal/1/collectinfo-2015-07-14T215632-ns_1%40172.23.107.191.zip
https://s3.amazonaws.com/cb-customers/rebal/1/collectinfo-2015-07-14T215632-ns_1%40172.23.107.194.zip