Unable to resume session after terminating a stuck job (cycle resolution)

This issue is 100% reproducible on 201310-14248, a HP laptop.

The resolution cycling job would stuck, if you terminate the canonical-certification-client by closing the GUI, it will print the following error message in the terminal, and it took a while to time out for "not receiving a reply":
GuiEngine::ResumeFromManualInteraction()
GuiEngine::RunCommand
GuiEngine::RunCommand
GuiEngine::Shutdown()
Failed to exit Plainbox "Did not receive a reply. Possible causes include: the remote application did not send a reply, the message bus security policy blocked the reply, the reply timeout expired, or the network connection was broken."

If you check processes status with "ps aux | grep box", it shows that the xrandr job still running in the background.
ubuntu@201310-14248:~$ ps aux | grep box
ubuntu 10617 2.9 0.6 531140 48736 ? Sl 02:53 1:02 /usr/bin/python3 /usr/bin/checkbox service
ubuntu 11919 0.0 0.1 40080 8544 ? S 03:22 0:00 python3 /tmp/nest-c7llakrv.313f723e0f5461f613c0d2322880cc8f54ba097f5530724d78451b2530ccc652/xrandr_cycle --screenshot-dir /home/ubuntu/.cache/plainbox/sessions/pbox-ctffd5vv.session/CHECKBOX_DATA

If you run canonical-certificaion-client again, it won't resume the session that you just interrupted.
ubuntu@201310-14248:~$ canonical-certification-client
GuiEngine::GuiEngine
GuiEngine::GuiEngine - Done
GuiEngine::Initialise
GuiEngine - Initialising
GuiEngine::RefreshPBObjects
Could not introspect this object
GuiEngine::RefreshPBObjects - Done
GuiEngine::Initialise() - Done
WhiteListModelFactory::CreateWhiteListModel()
Recreating TestItemModel
WhiteListModelFactory::CreateWhiteListModel() - Done
Failed to CreateSession()
GuiEngine::PreviousSessionFile()
process 11997: arguments to dbus_message_new_method_call() were incorrect, assertion "_dbus_check_is_valid_path (path)" failed in file ../../dbus/dbus-message.c line 1267.
This is normally a bug in some application using the D-Bus library.
process 11997: arguments to dbus_message_set_auto_start() were incorrect, assertion "message != NULL" failed in file ../../dbus/dbus-message.c line 2952.
This is normally a bug in some application using the D-Bus library.
process 11997: arguments to dbus_message_iter_init_append() were incorrect, assertion "message != NULL" failed in file ../../dbus/dbus-message.c line 2349.
This is normally a bug in some application using the D-Bus library.
QDBusConnection: error: could not send message to service "com.canonical.certification.PlainBox1" path "" interface "org.freedesktop.DBus.Introspectable" member "Introspect":
GuiEngine::Shutdown()

Same thing applies to when you hit ctrl + c in the terminal to terminate the GUI.

It's note worthy that if you kill the processes with "pkill -f box" before restarting checkbox, this resolution cycle job won't be stuck again. It will finish the testing, but also open a window for "shutter" program, which is never happen before.

Version information:
ubuntu@201310-14248:~$ apt-cache policy checkbox
checkbox:
  Installed: 0.17.10+bzr2829+pkg77+legacy1~ubuntu14.04.1
  Candidate: 0.17.10+bzr2829+pkg77+legacy1~ubuntu14.04.1
  Version table:
 *** 0.17.10+bzr2829+pkg77+legacy1~ubuntu14.04.1 0
        500 http://ppa.launchpad.net/checkbox-dev/ppa/ubuntu/ trusty/main amd64 Packages
        100 /var/lib/dpkg/status
     0.17.6-0ubuntu6 0
        500 http://us.archive.ubuntu.com/ubuntu/ trusty/universe amd64 Packages
ubuntu@201310-14248:~$ apt-cache policy plainbox
plainbox:
  Installed: 0.20+bzr3556+pkg23~ubuntu14.04.1
  Candidate: 0.20+bzr3556+pkg23~ubuntu14.04.1
  Version table:
 *** 0.20+bzr3556+pkg23~ubuntu14.04.1 0
        500 http://ppa.launchpad.net/checkbox-dev/ppa/ubuntu/ trusty/main amd64 Packages
        100 /var/lib/dpkg/status
     0.5.3-2 0
        500 http://us.archive.ubuntu.com/ubuntu/ trusty/universe amd64 Packages
ubuntu@201310-14248:~$ plainbox dev list provider
provider '2013.com.canonical.certification:certification-client'
provider '2013.com.canonical.certification:checkbox'
provider '2013.com.canonical.certification:plainbox-resources'