sometimes core_filters is not an attribute, so just set it to empty instead of pop

awx/main/managers.py

@@ -40,7 +40,7 @@ class HostManager(models.Manager):
                     #
                     # If we don't disable this, a filter of {'inventory': self.instance} gets automatically
                     # injected by the related object mapper.
-                    self.core_filters.pop('inventory', None)
+                    self.core_filters = {}
 
                     qs = qs & q
                     unique_by_name = qs.order_by('name', 'pk').distinct('name')