Swap rebalance failed in high bucket density test

Build 6.5.0-3633

Observed that swap second swap rebalance for kv has failed while running high bucket density(30 bucket) test.

Node 172.23.97.14 was coming in and 172.23.97.15 was going out.

Job- http://perf.jenkins.couchbase.com/job/arke-multi-bucket/310/

Logs-

https://s3-us-west-2.amazonaws.com/perf-artifacts/jenkins-arke-multi-bucket-310/172.23.97.14.zip 
https://s3-us-west-2.amazonaws.com/perf-artifacts/jenkins-arke-multi-bucket-310/172.23.97.15.zip

In logs we see error-

Node ('ns_1@172.23.97.14') was automatically failed over. Reason: The data service is online but the following buckets' data are not accessible: bucket-19.