Intermittent failure in create partitioned index with num_replica

Build : 6.5.0-4821

Sometimes, create partitioned index with replicas are failing with the following error:

[
{
"code": 5000,
"msg": "GSI CreateIndex() - cause: Fail to create index due to rebalancing, another concurrent request, network partition, or node failed. The operation may have succeed. If not, please retry the operation at later time.",
"query": "CREATE INDEX idx3 on `beer-sample`(name,city) partition by hash(name) with

"
}
]

This is not 100% consistent, but can be easily reproduced.

Steps :
1. 4 node cluster with indexing service on all 4 nodes
2. Install beer sample bucket
3. Optional step : curl localhost:9102/settings/planner?excludeNode=in -u Administrator:password on node 0 (Issue can be seen without this step as well)
4. Create index :
CREATE INDEX idx3 on `beer-sample`(name,city) partition by hash(name) with

This statement will fail sometimes with the above mentioned error.

Seeing several failures related to this bug in the functional regression since 6.5.0-4783. Last known good build was 6.5.0-4744.

There are some planner related changes that went in between 6.5.0-4744 and 6.5.0-4783 that might have caused this regression.
http://172.23.123.43:8000/getchangelog?product=couchbase-server&fromb=6.5.0-4744&tob=6.5.0-4783