Zombie queue members landing in random voicemail boxes

I am having some problems with a queue that is creating zombie channels and somehow they drop off into random voicemail boxes. I am not sure if I am the only person with this problem, but I have seen other tickets for it that were excused as too high volume to a queue, which is not what FreePBX is designed for. We only have 8 analog lines, which I believe is well within the FreePBX capabilities.

I have a feeling that I might be posting this in the wrong place, but I am a bit delirious at this point after sleeping about 6 hours in 3 days. lol

Here is what is happening.

We have the 8 analog channels ringing to x200 (Receptionist). She diverts about 90% of the calls to the Customer Service Queue 600. We have between 1 and 6 agents logged in, depending on the time of day and date. Failover destination is another queue that has other extensions logged in in case 600 is bombarded.

I can't deliberately replicate the problem... but... When it happens, the caller is answered by x200... transferred to 600 queue, then has about 2 seconds of the hold recording, then is sent to a voicemail box for a random person in the company. Almost all have been agents in the queues, but a couple have been completely non-related extensions, which increases the mystery.

Like I said, I can't make it happen when I want... but it is happening about 5% if the calls that are coming in, making very unhappy customers out of those individuals and an irate Customer Service Manager.

I am seeing this type of log entries... and I do not see it leave the 600 queue to the failover destination...

[2014-08-01 08:06:11] VERBOSE[2881][C-00002a44] res_musiconhold.c: – Stopped music on hold on SIP/200-0000409d
[2014-08-01 08:06:11] VERBOSE[2881][C-00002a44] res_musiconhold.c: – Stopped music on hold on DAHDI/7-1
[2014-08-01 08:06:11] VERBOSE[28271][C-00002a44] pbx.c: – Executing [h@macro-dial-one:1] Macro("SIP/200-0000409d<ZOMBIE>", "hangupcall,") in new stack
[2014-08-01 08:06:11] VERBOSE[28271][C-00002a44] pbx.c: – Executing [s@macro-hangupcall:1] GotoIf("SIP/200-0000409d<ZOMBIE>", "1?theend") in new stack
[2014-08-01 08:06:11] VERBOSE[28271][C-00002a44] pbx.c: – Goto (macro-hangupcall,s,3)
[2014-08-01 08:06:11] VERBOSE[28271][C-00002a44] pbx.c: – Executing [s@macro-hangupcall:3] ExecIf("SIP/200-0000409d<ZOMBIE>", "0?Set(CDR(recordingfile)=)") in new stack
[2014-08-01 08:06:11] VERBOSE[28271][C-00002a44] pbx.c: – Executing [s@macro-hangupcall:4] Hangup("SIP/200-0000409d<ZOMBIE>", "") in new stack
[2014-08-01 08:06:11] VERBOSE[28271][C-00002a44] app_macro.c: == Spawn extension (macro-hangupcall, s, 4) exited non-zero on 'SIP/200-0000409d<ZOMBIE>' in macro 'hangupcall'
[2014-08-01 08:06:11] VERBOSE[28271][C-00002a44] pbx.c: == Spawn extension (macro-dial-one, h, 1) exited non-zero on 'SIP/200-0000409d<ZOMBIE>'
[2014-08-01 08:06:11] VERBOSE[28271][C-00002a44] app_macro.c: == Spawn extension (macro-dial-one, s, 43) exited non-zero on 'SIP/200-0000409d<ZOMBIE>' in macro 'dial-one'
[2014-08-01 08:06:11] VERBOSE[28271][C-00002a44] app_macro.c: == Spawn extension (macro-exten-vm, s, 16) exited non-zero on 'SIP/200-0000409d<ZOMBIE>' in macro 'exten-vm'
[2014-08-01 08:06:11] VERBOSE[28271][C-00002a44] pbx.c: == Spawn extension (from-did-direct, 200, 2) exited non-zero on 'SIP/200-0000409d<ZOMBIE>'

[2014-08-01 08:06:26] VERBOSE[28310][C-00002a46] app_queue.c: – Nobody picked up in 15000 ms
[2014-08-01 08:06:26] VERBOSE[28310][C-00002a46] app_queue.c: – LazyMembers debugging - Numbusies: 0, Numnoans2: 0, Nummems: 1
[2014-08-01 08:06:26] VERBOSE[28312][C-00002a46] app_macro.c: == Spawn extension (macro-dial-one, s, 43) exited non-zero on 'Local/325@from-queue-00000b04;2' in macro 'dial-one'
[2014-08-01 08:06:26] VERBOSE[28312][C-00002a46] app_macro.c: == Spawn extension (macro-exten-vm, s, 16) exited non-zero on 'Local/325@from-queue-00000b04;2' in macro 'exten-vm'
[2014-08-01 08:06:26] VERBOSE[28312][C-00002a46] pbx.c: == Spawn extension (from-internal, 325, 2) exited non-zero on 'Local/325@from-queue-00000b04;2'
[2014-08-01 08:06:26] VERBOSE[28312][C-00002a46] pbx.c: – Executing [h@from-internal:1] Hangup("Local/325@from-queue-00000b04;2", "") in new stack
[2014-08-01 08:06:26] VERBOSE[28312][C-00002a46] pbx.c: == Spawn extension (from-internal, h, 1) exited non-zero on 'Local/325@from-queue-00000b04;2'