Confbridge doesnt end when end_marked user exits

I am creating a conference using originate() and confbridge() in the dialplan.
Then I want to kick the confbridge such that if any user quits the conference, the confbridge should end. But it is not happening in the following configuration.
As of now, confbridge ends only when originator is kicked out of conference.
Can somebody tell what is the problem here?
Thanks.

------------------------------------------ OUTPUT-1 ----------------------------------------------
Moxa*CLI> confbridge list 4
Channel User Profile Bridge Profile Menu CallerID
============================= ================ ================ ================ ================
SIP/101-0000000a default_user default_bridge
SIP/chetan-00000009 src_user default_bridge chetan
SIP/102-0000000b default_user default_bridge

Moxa*CLI> confbridge kick 4 SIP/101-0000000a
Participant ‘SIP/101-0000000a’ kicked out of conference ‘4’

Moxa*CLI> confbridge list 4
Channel User Profile Bridge Profile Menu CallerID
============================= ================ ================ ================ ================
SIP/chetan-00000009 src_user default_bridge chetan
SIP/102-0000000b default_user default_bridge

MoxaCLI>
--------------------------------------------------OUTPUT-2 ----------------------------------------
Moxa
CLI> confbridge list 9
Channel User Profile Bridge Profile Menu CallerID
============================= ================ ================ ================ ================
SIP/101-00000017 default_user default_bridge
SIP/102-00000018 default_user default_bridge
SIP/chetan-00000016 src_user default_bridge chetan

Moxa*CLI> confbridge kick 9
SIP/101-00000017 SIP/102-00000018 SIP/chetan-00000016

Moxa*CLI> confbridge kick 9 SIP/chetan-00000016
Participant ‘SIP/chetan-00000016’ kicked out of conference ‘9’

Moxa*CLI> confbridge list 9
No conference bridge named ‘9’ found!

Moxa*CLI> confbridge list
Conference Bridge Name Users Marked Locked?
================================ ====== ====== ========

-------------------------------------------------------------------------------------------------------

Following is the configuration:
-------------------------------------------- confbridge.conf ----------------------------------------

[default_bridge]
type=bridge

[default_user]
type=user
end_marked=yes
quiet=yes
startmuted=yes

[src_user]
type=user
marked=yes
quiet=yes
--------------------------------- extensions.conf -----------------------------------
[macro-setext]
exten => s,1,Set(DB(PA/dev1)=101)
exten => s,n,Set(DB(PA/dev2)=102)
exten => s,n,Set(DB(PA/dev3)=0)
exten => s,n,Set(DB(LPA_1/dev1)=101)
exten => s,n,Set(DB(LPA_1/dev2)=102)
exten => s,n,Set(DB(LPA_1/dev3)=0)
exten => s,n,Set(DB(LPA_2/dev1)=101)
exten => s,n,Set(DB(LPA_2/dev2)=0)
exten => s,n,Set(DB(CONF/NUM)=0)
exten => s,n,Set(DB(CONF/PA_LAST_CHAN)=0)

[default]
;Following statement sets some variables in the database
exten => setE,1,Macro(setext)

; LPA extensions dialplan
exten => _LPA_x,1,Answer()
exten => _LPA_x,n,System(/home/aster/sbin/asterisk -C /home/aster/etc/asterisk/a
exten => _LPA_x,n,Set(DB(CONF/PA_LAST_CHAN)=${CHANNEL})
exten => _LPA_x,n,Set(ID=$[${DB(CONF/NUM)}+1])
exten => _LPA_x,n,Set(DB(CONF/NUM)=${ID})
exten => _LPA_x,n,Set(i=1)
exten => _LPA_x,n,Set(target=${DB(${EXTEN}/dev${i})})
exten => _LPA_x,n,While(${target} != 0)
exten => _LPA_x,n,Originate(SIP/${target},app,confBridge,${ID},default_user)
exten => _LPA_x,n,Set(i=$[${i} + 1])
exten => _LPA_x,n,Set(target=${DB(${EXTEN}/dev${i})})
exten => _LPA_x,n,NoOp(target to dial is : ${target})
exten => _LPA_x,n,EndWhile()
exten => _LPA_x,n,NoOp(CONF_ID is: ${ID})
exten => _LPA_x,n,confbridge(${ID},src_user)

------------------------------------------- sip.conf ------------------------------------------
[general]
context=default
disallow=all
allow=alaw
allow=ulaw
allow=gsm
canreinvite=yes
directmedia=yes
dtmfmode=rfc2833
insecure = port

[chetan]
host=dynamic
type=friend
username=chetan
secret=chetan

[101]
host=dynamic
type=friend

[102]
host=dynamic
type=friend
------------------------------------------------------------------------------------------