Rebalance exited with reason "bad_replicas" during rebalacing in 1 node, on a single node cluster

Setup
1. Create a bucket on a single node cluster. ( 2 replicas)
2. Load 1M items on this node
3. Add 1 node and rebalance

Error
Rebalance failed with error " bad replicas"
Bad replicators after rebalance:
Missing = [

{'ns_1@10.3.121.37','ns_1@10.3.121.38',0}

,

{'ns_1@10.3.121.37','ns_1@10.3.121.38',1}

,

{'ns_1@10.3.121.37','ns_1@10.3.121.38',2}

,

{'ns_1@10.3.121.37','ns_1@10.3.121.38',3}

,

{'ns_1@10.3.121.37','ns_1@10.3.121.38',4}

,

{'ns_1@10.3.121.37','ns_1@10.3.121.38',5}

,

{'ns_1@10.3.121.37','ns_1@10.3.121.38',6}

,

{'ns_1@10.3.121.37','ns_1@10.3.121.38',7}

,

{'ns_1@10.3.121.37','ns_1@10.3.121.38',8}

,

{'ns_1@10.3.121.37','ns_1@10.3.121.38',9}

,

{'ns_1@10.3.121.37','ns_1@10.3.121.38',10}

,

{'ns_1@10.3.121.37','ns_1@10.3.121.38',11}

,

{'ns_1@10.3.121.37','ns_1@10.3.121.38',12}

]
Extras = []

Output from ns_server logs show

Adding logs from the servers.