Traceback after running oaconfig install a second time

Checking Ceph cluster ceph (e6597ef5-cacc-4315-bbc1-c56a2b62beba)...
Traceback (most recent call last):
  File "manage.py", line 26, in <module>
    execute_from_command_line(sys.argv)
  File "/usr/lib/python2.7/dist-packages/django/core/management/__init__.py", line 354, in execute_from_command_line
    utility.execute()
  File "/usr/lib/python2.7/dist-packages/django/core/management/__init__.py", line 346, in execute
    self.fetch_command(subcommand).run_from_argv(self.argv)
  File "/usr/lib/python2.7/dist-packages/django/core/management/base.py", line 394, in run_from_argv
    self.execute(*args, **cmd_options)
  File "/usr/lib/python2.7/dist-packages/django/core/management/base.py", line 445, in execute
    output = self.handle(*args, **options)
  File "/srv/openattic/backend/sysutils/management/commands/post_install.py", line 49, in handle
    sysutils.models.post_install.send(sender=sysutils.models)
  File "/usr/lib/python2.7/dist-packages/django/dispatch/dispatcher.py", line 189, in send
    response = receiver(signal=self, sender=sender, **named)
  File "/srv/openattic/backend/ceph/management/__init__.py", line 60, in update
    cluster = ceph_models.Cluster.objects.get(uuid=conf.get("global", "fsid"))
  File "/usr/lib/python2.7/dist-packages/django/db/models/manager.py", line 127, in manager_method
    return getattr(self.get_queryset(), name)(*args, **kwargs)
  File "/usr/lib/python2.7/dist-packages/django/db/models/query.py", line 338, in get
    (self.model._meta.object_name, num)
ceph.models.MultipleObjectsReturned: get() returned more than one Cluster -- it returned 2!

    cluster e6597ef5-cacc-4315-bbc1-c56a2b62beba
     health HEALTH_OK
     monmap e1: 1 mons at {<hostname>=<IP>:6789/0}
            election epoch 5, quorum 0 <hostname>
      fsmap e15: 1/1/1 up {0=0=up:active}
     osdmap e27: 1 osds: 1 up, 1 in
            flags sortbitwise
      pgmap v6817: 120 pgs, 8 pools, 3704 bytes data, 191 objects
            3952 MB used, 9025 MB / 13695 MB avail
                 120 active+clean