rebalance fails with bucket_engine error : bucket_engine.c:1876: bucket_engine_release_cookie: Assertion `peh' failed

rebalance is failing on the latest v0.0.0. 132 builds with these error messages :

error messages:

Port server memcached on node 'ns_1@10.1.5.228' exited with status 134. Restarting. Messages: memcached: bucket_engine.c:1876: bucket_engine_release_cookie: Assertion `peh' failed

Rebalance exited with reason {badmatch,{error,closed,
[

{mc_client_binary,cmd_binary_vocal_recv,5}

,

{mc_client_binary,get_vbucket,2}

,

{ns_memcached,handle_call,3}

,

{gen_server,handle_msg,5}

,

{proc_lib,init_p_do_apply,3}

]},
{gen_server,call,
[

{'ns_memcached-default','ns_1@10.1.5.228'}

,

{get_vbucket,512}

,
30000]}}
ns_orchestrator002 ns_1@10.1.5.227 11:23:55 - Tue Apr 12, 2011
Control connection to memcached on 'ns_1@10.1.5.228' disconnected: {{badmatch,
{error,
closed}},
[

{mc_client_binary, cmd_binary_vocal_recv, 5}

,

{mc_client_binary, get_vbucket, 2}

,

{ns_memcached, handle_call, 3}

,

{gen_server, handle_msg, 5}

,
{proc_lib,
init_p_do_apply,

steps to reproduce :

1- install
2- create bucket 'default'
3- add node X
4- rebalance
5- remove X
6- rebalance

rebalance fails in step 4 and step 6