Transition error while resource allocation

[jihoonl]

[INFO] [WallTime: 1427778097.544853] Scheduler : compatibility tree is valid, attempting to allocate [91437f50-fc57-4e20-9373-f15cdacf460c]
[WARN] [WallTime: 1427778111.714549] Hub Watcher: gateway bach168416d32b0f47a58f979775267207e1 has been unavailable for 10 seconds! Marking as unavailable.
[INFO] [WallTime: 1427778112.475502] Conductor : concert client transition [available->missing][bach1]
[INFO] [WallTime: 1427778119.639819] Scheduler :   allocated [bach1]
[ERROR] [WallTime: 1427778119.643354] bad callback: <bound method CompatibilityTreeScheduler._ros_subscriber_concert_client_changes of <concert_schedulers.compatibility_tree_scheduler.scheduler.CompatibilityTreeScheduler object at 0x7f3ccbeb6ed8>>
Traceback (most recent call last):
  File "/opt/ros/indigo/lib/python2.7/dist-packages/rospy/topics.py", line 702, in _invoke_callback
    cb(msg)
  File "/home/jihoonl/research/ros/creativa_tc/src/rocon_concert/concert_schedulers/src/concert_schedulers/compatibility_tree_scheduler/scheduler.py", line 146, in _ros_subscriber_concert_client_changes
    pending_notifications.extend(self._update(external_update=True))
  File "/home/jihoonl/research/ros/creativa_tc/src/rocon_concert/concert_schedulers/src/concert_schedulers/compatibility_tree_scheduler/scheduler.py", line 301, in _update
    reply.grant(resources)
  File "/home/jihoonl/research/ros/creativa_tc/src/concert_scheduling/concert_scheduler_requests/src/concert_scheduler_requests/transitions.py", line 310, in grant
    self._transition(EVENT_GRANT, reason=Request.NONE)
  File "/home/jihoonl/research/ros/creativa_tc/src/concert_scheduling/concert_scheduler_requests/src/concert_scheduler_requests/transitions.py", line 228, in _transition
    + ' in state ' + STATE_NAME[self.msg.status])
TransitionError: invalid event grant in state GRANTED