Backtrace after calling subscriber with external conversatio

[Prost]

Hello,
I has OXE Crystal HW with 9.0 Release (h130150c)
UserA (internal number 4188, equipment number 1131, set type 4020)
UserB (internal number 4139, equipment number 1068, set type 4020, don't has multiline keys). With analog user B same issue.

User B has conversation with external subscriber (via SIP or T2). If user B has conversation with internal user all OK.

- User A call user B
- User A hearing short message (1 sec) what user busy and after that busy tone and can't to make callback on user B
After that I see backtraces:
incvisu
26/09/14 15:06:10 000001M|---/--/-/---|=0:1721=Phone exc 5, PC 0x0936cef6 neqt 1131

excvisu
There is a new exception. Its address is : 0X0936CEF6. Monitel time : 6490328. Date : Fri Sep 26 15:06:10 2014
Application-exception no 5, thd 1091, PC=0x0936cef6:154586870, eqt=1131, serv=0 --> __CHECK__
Eqt type=POS_NUM, cr=0, cpl=22, der_us=0, term=24, subtype = 4012(LE)
* Backtrace: 0x08326bf5:137522165 EBP 0x01846b38 --> poste_MLA
* Backtrace: 0x4013e87d:1075046525 EBP 0x01846b5c --> myStop_VMU_Timer
* Backtrace: 0x08a50552:145032530 EBP 0x01846b94 --> ch_afficenra
* Backtrace: 0x08a4db85:145021829 EBP 0x01846bc0 --> afficenra
* Backtrace: 0x08b3fbd2:146013138 EBP 0x01846bcc --> invit_eetrapat
* Backtrace: 0x08a3611b:144924955 EBP 0x01846bec --> v_renvoc_imp
* Backtrace: 0x08a361cd:144925133 EBP 0x01846bfc --> renvoc_imp
* Backtrace: 0x08a373e9:144929769 EBP 0x01846c04 --> t_occup
* Backtrace: 0x09203a86:153107078 EBP 0x01846c7c --> t_occup_prio
* Backtrace: 0x0920a8c2:153135298 EBP 0x01846c84 --> v_t_occup_prio
* Backtrace: 0x08a029d9:144714201 EBP 0x01846c98 --> sui_credloc
* Backtrace: 0x08a02b41:144714561 EBP 0x01846cac --> credloc
* Backtrace: 0x08a03278:144716408 EBP 0x01846cc0 --> test_s63
* Backtrace: 0x08a03b0b:144718603 EBP 0x01846cd4 --> postbon
* Backtrace: 0x08a03e7a:144719482 EBP 0x01846d0c --> esaploc
* Backtrace: 0x08a03ff1:144719857 EBP 0x01846d30 --> rech_ou_aploc
* Backtrace: 0x08a046f5:144721653 EBP 0x01846d3c --> aplourv
* Backtrace: 0x08a04de0:144723424 EBP 0x01846df8 --> appeloc
* Backtrace: 0x08a060e1:144728289 EBP 0x01846e18 --> loc_rsvp
* Backtrace: 0x08a6d63d:145151549 EBP 0x01846e3c --> reptrad_local_station
* Backtrace: 0x08a700ad:145162413 EBP 0x01846e54 --> sui_decreptrad
* Backtrace: 0x08a702f4:145162996 EBP 0x01846e6c --> decreptrad
* Backtrace: 0x08a06d19:144731417 EBP 0x01846e7c --> tra_dec
* Backtrace: 0x092d39f2:153958898 EBP 0x01846ec0 --> real_main
GS=00000000 FS=00000000 ES=0000002b DS=0000002b
EDI=4006b5d0 ESI=4006b6d8 EBP=01846b38 ESP0=00000000
EBX=00000001 EDX=00000001 ECX=000000ff EAX=08326bf5
EIP=0936cef6 CS=00000023 ESP3=01846b38 EFLAGS=00010293