Rebalance hang in online upgrade from 2.5.1 to 4.6.2

Install Couchbase Server 2.5.1 on 3 nodes (101, 133 and 172)

Create default and bucket0 bucket

Create 2 'Production Views'  views V1 and V2 on default bucket

Load 10K items to each bucket.

Install Couchbase Server 4.6.2-3900 on node 122

Add node 122 to 2.5.1 cluster and remove node 172.

Rebalance (swap rebalance).  Rebalance hang when it starts to rebalance second bucket (default bucket with views).

Live node available to debug at 172.23.106.101, 105.133, ....

I don't see any moving in vbuckets at all as in capture pic