diff --git a/readthedocs/search/views.py b/readthedocs/search/views.py
index 30504b93a18..5a207bdd9bd 100644
--- a/readthedocs/search/views.py
+++ b/readthedocs/search/views.py
@@ -60,7 +60,7 @@ def elastic_search(request, project_slug=None):
         index=request.GET.get('index'),
     )
     search_facets = collections.defaultdict(
-        ProjectSearch,
+        lambda: ProjectSearch,
         {
             'project': ProjectSearch,
             'domain': DomainSearch,