The first one works, the second doesn't find the cursor, and the last asserts:

Wed Oct 19 13:35:48 [conn25] killcursors: found 0 of 1
Wed Oct 19 13:35:48 [conn25] Assertion: 13658:bad kill cursors size: 32
0x1000898dd 0x1003deddc 0x1003e272a 0x100603394 0x100148d8c
0x10060a554 0x7fff88ecefd6 0x7fff88ecee89
0 mongod 0x00000001000898dd
_ZN5mongo11msgassertedEiPKc + 333
1 mongod 0x00000001003deddc
_ZN5mongo19receivedKillCursorsERNS_7MessageE + 1900
2 mongod 0x00000001003e272a
_ZN5mongo16assembleResponseERNS_7MessageERNS_10DbResponseERKNS_11HostAndPortE
+ 794
3 mongod 0x0000000100603394
_ZN5mongo16MyMessageHandler7processERNS_7MessageEPNS_21AbstractMessagingPortEPNS_9LastErrorE
+ 148
4 mongod 0x0000000100148d8c
_ZN5mongo3pms9threadRunEPNS_13MessagingPortE + 700
5 mongod 0x000000010060a554 thread_proxy + 132
6 libSystem.B.dylib 0x00007fff88ecefd6 _pthread_start + 331
7 libSystem.B.dylib 0x00007fff88ecee89 thread_start + 13

Can we have a tamer message in the last case?