Rebalance fails with "bad match wait_backfill_determination" error on a very small load

Load 1M items on a 4 node cluster.
Rebalance in 2 nodes.

Rebalance and Compaction start in parallel.

Rebalance is very slow in initial few minutes, catches up, but fails with a timeout exit,

The load/cluster is a very basic configiuration. This is a working on 2.0

• • Reason for termination ==
  • {unexpected_exit,
    {'EXIT',<0.896.2>,
    {{badmatch,
    [{'EXIT',
    {timeout,
    {gen_server,call, [<20117.4759.0>,had_backfill,30000]}

    }}]},
    [

    {ns_single_vbucket_mover, '-wait_backfill_determination/1-fun-1-',1}

    ]}}}

[error_logger:error,2013-01-17T23:11:39.476,ns_1@10.176.169.6:error_logger<0.6.0>:ale_error_logger_handler:log_report:72]
=========================CRASH REPORT=========================
crasher:
initial call: ns_vbucket_mover:init/1
pid: <0.24152.1>
registered_name: []
exception exit: {unexpected_exit,
{'EXIT',<0.896.2>,
{{badmatch,
[{'EXIT',
{timeout,

{gen_server,call, [<20117.4759.0>,had_backfill,30000]}

}}]},
[

{ns_single_vbucket_mover, '-wait_backfill_determination/1-fun-1-',1}

]}}}
in function gen_server:terminate/6
ancestors: [<0.13807.1>]
messages: [{backfill_done,
{'ns_1@10.176.169.6',1019,
['ns_1@10.176.169.6','ns_1@10.169.54.218'],
['ns_1@10.176.155.132','ns_1@10.168.94.60']}},
{move_done_new_style,
{'ns_1@10.176.169.6',1019,
['ns_1@10.176.169.6','ns_1@10.169.54.218'],
['ns_1@10.176.155.132','ns_1@10.168.94.60']}},

{'EXIT',<0.6884.2>,normal}

,
{backfill_done,
{'ns_1@10.169.54.218',678,
['ns_1@10.169.54.218','ns_1@10.168.173.242'],
['ns_1@10.168.94.60','ns_1@10.176.155.132']}},
{move_done_new_style,
{'ns_1@10.169.54.218',678,
['ns_1@10.169.54.218','ns_1@10.168.173.242'],
['ns_1@10.168.94.60','ns_1@10.176.155.132']}},

{'EXIT',<0.7095.2>,normal}

]
links: [<0.13807.1>,<0.24159.1>,<0.57.0>]
dictionary: [

{bucket_name,"default"}

,

{i_am_master_mover,true}

,

{child_processes,[<0.7095.2>,<0.6884.2>,<0.6760.2>, <0.3866.2>,<0.3858.2>,<0.862.2>,<0.855.2>, <0.852.2>,<0.787.2>,<0.26181.1>, <0.26131.1>,<0.26086.1>,<0.24174.1>, <0.24173.1>]}

]
trap_exit: true
status: running
heap_size: 28657
stack_size: 24
reductions: 1198089

Logs at