Disconnect second line when Hold Call hang up

Hi,all:

I have the follow symptom:

A call is received and answered in a extension, a new call ingress in the same extension. The new call is answered, and the first call is put in hold.

The problem is that the hold call (first call) is hang up by first caller, in a period of  time determined,approximately 5 seconds, and  second call is disconnected automatically.

This only happens with internal calls and first call from the PSTN.

What happens? thks

my config:

!
ephone-dn  3  dual-line
number 116
pickup-group 9
label xxx_116
name xxx_116
hold-alert 30 originator
!

!
voice-port 0/1/0
supervisory disconnect dualtone mid-call
cptone CN
timeouts interdigit 5
timeouts call-disconnect 5
timeouts wait-release 5
caller-id enable
!

!
dial-peer voice 10 pots
translation-profile incoming ext_add_9
translation-profile outgoing telcom
service aa
destination-pattern 9.T
port 0/1/0
!

!
telephony-service
max-ephones 58
max-dn 192
ip source-address 10.64.183.2 port 2000
timeouts interdigit 5
timeouts ringing 45
timeouts transfer-recall 20
system message AON-COFCO-GZ PHONE
time-zone 42
time-format 24
max-conferences 12 gain -6
moh flash:music-on-hold.au
web admin system name admin password aon123
web admin customer name aon123 password aon123
dn-webedit
time-webedit
transfer-system blind
secondary-dialtone 9
directory entry 1 910000 name test
create cnf-files version-stamp 7960 Mar 04 2010 12:35:17
!

I tried change all the transfer-system options,try no timeouts transfer-recall,can't fix the problem.