online upgrade from 2.0.0 to 3.0.0-847 failed due to items did not persisted to disk when all nodes swap to 3.0

Install couchbase server 2.0 to 2 nodes
1:10.6.2.112
2:10.6.2.113
Create a cluster with 3 buckets: default, standard and sasl
Load 1000 items to each bucket (only KV test)

Install couchbase server 3.0.0-847 on 2 nodes
3:10.3.3.224
4:10.3.121.241
Add node 3 and 4 to 2.0 cluster
Rebalance cluster. Passed
3.0 node becomes master. Passed
Remove 2 2.0 nodes
Rebalance out 2 2.0 nodes. Passed.
Test failed due to items did not persist to disk in all 3 buckets

root@ubuntu:~# /opt/couchbase/bin/cbstats 10.3.3.224:11211 all -b default | grep curr
curr_connections: 56
curr_conns_on_port_11207: 4
curr_conns_on_port_11209: 46
curr_conns_on_port_11210: 6
curr_items: 1000
curr_items_tot: 1162
curr_temp_items: 0
vb_active_curr_items: 1000
vb_pending_curr_items: 0
vb_replica_curr_items: 162
root@ubuntu:~# /opt/couchbase/bin/cbstats 10.3.3.224:11217 all | grep curr
curr_connections: 58
curr_conns_on_port_11207: 4
curr_conns_on_port_11209: 46
curr_conns_on_port_11210: 8
curr_items: 1000
curr_items_tot: 1162
curr_temp_items: 0
vb_active_curr_items: 1000
vb_pending_curr_items: 0
vb_replica_curr_items: 162
root@ubuntu:~# /opt/couchbase/bin/cbstats 10.3.3.224:11211 all -b bucket0 -p password | grep curr
curr_connections: 60
curr_conns_on_port_11207: 4
curr_conns_on_port_11209: 46
curr_conns_on_port_11210: 10
curr_items: 1000
curr_items_tot: 1158
curr_temp_items: 0
vb_active_curr_items: 1000
vb_pending_curr_items: 0
vb_replica_curr_items: 158

Live cluster is availabe for debug