Cannot sort by Group after adding users to a second LDAP group

[brian-emery]

In testing, I synced an LDAP group (OU) of 10k users with the OMVA. I then created a posix group in LDAP and appended half of the 10k users to it. I synced that group with the OMVA as well (with a higher priority). All users were properly moved from the first group to the second. However, attempting to sort by group now results in a 500 error in the browser. This is the error in the admin_console logs:

2015-08-11 08:16:24,074 ERROR   django.request : Internal Server Error: /users/
Traceback (most recent call last):
  File "/usr/local/lib/python2.7/dist-packages/django/core/handlers/base.py", line 113, in get_response
    response = callback(request, *callback_args, **callback_kwargs)
  File "/opt/openmanage/django/apps/blue_management/blue_mgnt/views/views.py", line 474, in new_fun
    request.session['username'], *args, **kwargs)
  File "/opt/openmanage/django/apps/blue_management/blue_mgnt/views/users.py", line 376, in users
    search_by=search_by,
  File "/opt/openmanage/django/apps/blue_management/blue_mgnt/views/views.py", line 412, in dec
    value = fun(*args, **kwargs)
  File "/opt/openmanage/netkes/account_mgr/accounts_api.py", line 31, in wrapper
    return func(*args, **kwargs)
  File "/opt/openmanage/netkes/account_mgr/accounts_api.py", line 229, in list_users
    return self.client.get_json('users/%s' % query_string)
  File "/opt/openmanage/netkes/account_mgr/api_client.py", line 62, in get_json
    return json.loads(self.get(path).read())
  File "/opt/openmanage/netkes/account_mgr/api_client.py", line 59, in get
    return self.open(path)
  File "/opt/openmanage/netkes/account_mgr/api_client.py", line 56, in open
    return self.opener.open(req)
  File "/usr/lib/python2.7/urllib2.py", line 406, in open
    response = meth(req, response)
  File "/usr/lib/python2.7/urllib2.py", line 519, in http_response
    'http', request, response, code, msg, hdrs)
  File "/usr/lib/python2.7/urllib2.py", line 444, in error
    return self._call_chain(*args)
  File "/usr/lib/python2.7/urllib2.py", line 378, in _call_chain
    result = func(*args)
  File "/usr/lib/python2.7/urllib2.py", line 527, in http_error_default
    raise HTTPError(req.get_full_url(), code, msg, hdrs, fp)
HTTPError: HTTP Error 400: Bad Request