rebalance fails with case_clause error

Created an attachment (id=748)
diag

1.6.0beta4-59

1) create 2 fresh nodes
2) join the nodes together
3) try to rebalance

Rebalance exited with reason {{case_clause,
{{ok,''},

{memcached_error,not_my_vbucket,<<>>}

}},
[

{ns_vbucket_mover,run_mover,5}

,

{ns_vbucket_mover,'-spawn_workers/1-fun-0-', 5}

]}