memcached crashes after adding a 1.8 node to 1.7.2 cluster

CRASH REPORT <0.2436.0> 2011-12-05 10:48:27
===============================================================================
Crashing process
initial_call

{mb_master,init,['Argument__1']}

pid <0.2436.0>
registered_name mb_master
error_info
{exit,{{case_clause,true},
[

{mb_master,higher_priority_node,3}

,

{mb_master,candidate,2}

,

{gen_fsm,handle_msg,7}

,

{proc_lib,init_p_do_apply,3}]},
[{gen_fsm,terminate,7},{proc_lib,init_p_do_apply,3}

]}
ancestors [ns_server_sup,ns_server_cluster_sup,<0.52.0>]
messages []
links [<0.118.0>,<0.2260.0>,<0.49.0>]
dictionary []
trap_exit true
status running
heap_size 2584
stack_size 24
reductions 746