moxi crash during item_free()

During weekend testing on a dev box (so, I'm not sure how to reproduce, but possibly related to memcapable), I saw a moxi crash report in the osx console...

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Application Specific Information:
Assertion failed: (it->refcount > 0), function item_free, file items.c, line 237.

Thread 0: Dispatch queue: com.apple.main-thread
0 libSystem.B.dylib 0x00007fff841bc4ea kevent + 10
1 libevent-1.4.2.dylib 0x0000000100111213 kq_dispatch + 83
2 libevent-1.4.2.dylib 0x0000000100104d28 event_base_loop + 440
3 moxi 0x00000001000179c6 main + 7022
4 moxi 0x0000000100000f04 start + 52

Thread 1:
0 libSystem.B.dylib 0x00007fff841bc4ea kevent + 10
1 libevent-1.4.2.dylib 0x0000000100111213 kq_dispatch + 83
2 libevent-1.4.2.dylib 0x0000000100104d28 event_base_loop + 440
3 moxi 0x000000010001fcad worker_libevent + 274
4 libSystem.B.dylib 0x00007fff841dc8b6 _pthread_start + 331
5 libSystem.B.dylib 0x00007fff841dc769 thread_start + 13

Thread 2 Crashed:
0 libSystem.B.dylib 0x00007fff8421601e __semwait_signal_nocancel + 10
1 libSystem.B.dylib 0x00007fff84215f20 nanosleep$NOCANCEL + 129
2 libSystem.B.dylib 0x00007fff84272902 usleep$NOCANCEL + 57
3 libSystem.B.dylib 0x00007fff84291eb8 abort + 93
4 libSystem.B.dylib 0x00007fff8427eef0 __pthread_markcancel + 0
5 moxi 0x000000010001c93c item_free + 99
6 moxi 0x000000010001cef5 do_item_remove + 38
7 moxi 0x000000010002046e item_remove + 38
8 moxi 0x00000001000025e6 conn_cleanup + 162
9 moxi 0x000000010000917a reset_cmd_handler + 76
10 moxi 0x0000000100012f8f drive_machine + 1907
11 moxi 0x000000010001459a event_handler + 285
12 libevent-1.4.2.dylib 0x0000000100105031 event_base_loop + 1217
13 moxi 0x000000010001fcad worker_libevent + 274
14 libSystem.B.dylib 0x00007fff841dc8b6 _pthread_start + 331
15 libSystem.B.dylib 0x00007fff841dc769 thread_start + 13