Cisco 3905 problem / remote site

Question

Hi all!
Information:
I have CUCM 8.6.2.20000-2 and many Cisco IP Phone 3905 (SIP). Some of them deployed in central office and some in remote sites.
Phone information:
Boot Version: 3905.0-0-0-01-01
DSP Version: 12.0.0.8
Application: 3905.9-2-2-0
Symptoms:
In remote sites only!
The phone is registered and working fine. However, after few hours idle state I lift the handset, dial any number and nothing happens. Drop the call and try again 2-3 times. After that either call passed or get permanent busy tone (need to reboot the phone to work again).
The phone is marked as registered on CUCM and I hear dial tone when lifted the handset.
I cannot collect debug messages from phones, because as soon as I login via telnet it going work fine.
There is no such problem in central office.
Phones print following messages in terminal all the time:
17:07:10:302 x [CENTRAL] CDP/LLDP-MED CB function is called
17:07:26:491   [sip]  03:58:24.490    pjsua_acc.c  SIP outbound status for acc 0 is not active
17:07:26:495   [sip]  03:58:24.494    pjsua_acc.c  "п°п╦я┘п╟п╦п╩ п я┐пЇя▄п╪п╦пҐ"<sip:[email protected]:5060>: registration success, status=200 (OK              ), will re-register in 120 seconds
17:07:26:502   [sip]  03:58:24.500         pjcu.c  pjcu_on_reg_state2(), Account["п°п╦я┘п╟п╦п╩ п я┐пЇя▄п╪п╦пҐ"<sip:[email protected]:5060>] : OK,               status=200
17:07:26:506 x [pcu] pcuRcvHandler(CALL), SRV_EV, eid=0, cid=65535,
17:07:26:510 x [pcu] [pcux_insrv_cb():7071] CUCM_DateTime:Mon, 27 May 2013 11:07:26 GMT
17:07:26:511 x [pcu] Sync time from server: Mon, 27 May 2013 11:07:26 GMT
17:07:26:515 x [pcu] [set_svr_type][1599] Bfe active_server_idx=0, serverType=0
17:07:26:515 x [pcu] [set_svr_type][1602] Aft  serverType=0, Server Number=2
17:07:26:531   [ipps] ----- PCU: CC_SRV, pid=0, eid=0, cid=65535 -----
17:07:26:532   [ipps] In func: remoteNtyEvtProcess(), lib = 0, cid = 65535, ntyEv = 0
17:07:26:533 f [ipps] In func: remoteNtyEvtProcess(), recv inservice nty, svrType = 0, cause = 0
17:07:26:534 f [MMI] <RCV>: In func: ui_nty(), lid = 0, cid = 65535, ntyEv = 0
17:07:26:535 x [CENTRAL] IPPS CB function(RegStatus) is called (1) with Line (0)
17:07:26:536 f [ipps] In func: mlcu_isKpmlEnabled(), KPML value = 3, blRet = 1
17:07:26:537 x [CENTRAL] Enter FSM: State(STANDBY) | Event(REGISTER_OK) | Cause(0)
17:07:26:540 x [CENTRAL] Unexpected event REGISTER_OK (cause=0) at STANDBY state
17:07:26:541 x [CENTRAL] Waiting event in STANDBY
17:07:58:990 x [CENTRAL] CDP/LLDP-MED CB function is called
17:08:39:022   [sip]  03:59:37.021         pjcu.c  pjcuRcvHandler(KA), KA_REQUEST, eid=-1, p1=192.168.70.1:5060
17:08:39:040   [sip]  03:59:37.036         pjcu.c  pjcu_rpt_ka_status(), target(192.168.70.1:5060): status=1, id=27
17:08:39:044 x [pcu] pcuRcvHandler(KA), KA_RESPONSE, eid=0, addr=192.168.70.1:5060, status=1
17:08:39:050 x [pcu] [pcu_polling_sipserver_thread():1478] mark!
17:08:54:130 x [CENTRAL] CDP/LLDP-MED CB function is called
Thanks for your help.

Answer 1

There are 2 versions of firmware on cisco.com. cmterm-3905.9-2-1-0 is the default firmware going with CUCM 8.6.2.20000-2 for 3905 phones and cmterm-3905.9-2-2-0 I've installed recently. Both versions of firmware with same problems.
       Some new information. I get traffic dump with wireshark.
INVITE sip:[email protected]:5060;transport=tcp SIP/2.0
Via: SIP/2.0/TCP 192.168.70.86:3457;rport;branch=z9hG4bKPjdp3HjFLs7Dy03RL9ce.16qung.tOq5O3
Max-Forwards: 70
From: "............ .............." ;tag=5a25b465-747b-4c31-a020-1a9636827427
To: sip:[email protected]
Contact: ;+sip.instance="";+u.sip!devicename.ccm.cisco.com="SEP10BD18DD3F59";+u.sip!model.ccm.cisco.com="592"
Call-ID: e9edcc43-6a9b-42b8-8efc-99f702b313d1
CSeq: 28324 INVITE
Allow: PRACK, INVITE, ACK, BYE, CANCEL, UPDATE, SUBSCRIBE, NOTIFY, REFER, MESSAGE, OPTIONS
User-Agent: Cisco-CP3905/9.2.1
Supported: replaces,join,sdp-anat,norefersub,extended-refer,X-cisco-callinfo,X-cisco-serviceuri,X-cisco-escapecodes,X-cisco-service-control,X-cisco-monrec,X-cisco-config,X-cisco-sis-4.0.0,X-cisco-xsi-7.0.1
Expires: 900
Accept: application/sdp
Allow-Events: kpml,dialog
Remote-Party-ID: "............ ..............";privacy=off
Content-Type: application/sdp
Content-Length:   294
As you can see phone trying to invite [email protected]:5060, BUT I dial 7103 DN from 7102. So where are other numbers? Bug?