moxi crashes under binary memcachetest populate

I was looking to get stats from moxi using netcat, and while doing so moxi seems to have crashed. I don't know if the two are related, but what log I have from moxi shows:

1. tail /var/tmp/moxi.out
   2010-08-29 03:28:37: (memcached.c.3024) 42: Client using the proxy-upstream-binary protocol
   2010-08-29 03:28:37: (memcached.c.3024) 50: Client using the proxy-upstream-binary protocol
   2010-08-29 03:28:37: (memcached.c.3024) 54: Client using the proxy-upstream-binary protocol
   2010-08-29 03:28:37: (memcached.c.3024) 52: Client using the proxy-upstream-binary protocol
   2010-08-29 03:28:37: (memcached.c.3024) 48: Client using the proxy-upstream-binary protocol
   2010-08-29 03:28:37: (memcached.c.3024) 56: Client using the proxy-upstream-binary protocol
   2010-08-29 03:28:37: (memcached.c.457) event_ad
   2010-08-29 03:28:37: (thread.c.298) Can't listen for events on fd 62
   2010-08-29 03:28:37: (memcached.c.3024) 62: Client using the proxy-upstream-ascii protocol
   moxi: cproxy_protocol_b.c:282: cproxy_process_downstream_binary: Assertion `d->upstream_conn != ((void *)0)' failed.

The memcachetest command used is:
/opt/memcachetestv/bin/memcachetest -i 6000000 -L 2 -t 16

-L2 is binary protocol, and -t 16 is 16 threads. They were all going to a single local moxi process, connected to a cluster of downstream membase nodes.