rebalance failed with "gen_fsm,sync_send_event," error during online upgrade from 1.7.2 to 1.8.1 on windows ( workaround is to wait 30 seconds between add_node and starting the rebalance )

Install membase server 1.7.2r-20 on 4 nodes windows server 2008 R2 64bit and couchbase server 1.8.0-810 on one node.
Create 4 nodes cluster of membase server 1.7.2.
Load 1000000 items to default bucket.
Add node 200 with couchbase server 1.8.1-810 to cluster.
Rebalance. Failed
Try rebalance one more time. Complete rebalance.

Error in log page
Server error during processing: ["web request failed",

{path,"/controller/rebalance"}

,

{type,exit}

,
{what,
{noproc,
{gen_fsm,sync_send_event,
[

{global,ns_orchestrator}

,

{start_rebalance, ['ns_1@10.3.121.182', 'ns_1@10.3.121.183', 'ns_1@10.3.121.201', 'ns_1@10.3.121.202', 'ns_1@10.3.121.200'], [],[]}

]}}},
{trace,
[

{gen_fsm,sync_send_event,2}

,

{menelaus_web,do_handle_rebalance,3}

,

{menelaus_web,loop,3}

,

{mochiweb_http,headers,5}

,

{proc_lib,init_p_do_apply,3}

]}]