diff --git a/openslides/utils/collection.py b/openslides/utils/collection.py
index 3cd25aefd..0b4709507 100644
--- a/openslides/utils/collection.py
+++ b/openslides/utils/collection.py
@@ -38,7 +38,12 @@ class CollectionElement:
         self.information = information or {}
         if instance is not None:
             self.collection_string = instance.get_collection_string()
-            self.id = instance.pk
+            from openslides.core.config import config
+            if self.collection_string == config.get_collection_string():
+                # For config objects we do not work with the pk but with the key.
+                self.id = instance.key
+            else:
+                self.id = instance.pk
         elif collection_string is not None and id is not None:
             self.collection_string = collection_string
             self.id = id
@@ -144,8 +149,7 @@ class CollectionElement:
             # The config instance has to be get from the config element, because
             # some config values are not in the db.
             from openslides.core.config import config
-            if (self.collection_string == config.get_collection_string() and
-                    isinstance(self.id, str)):
+            if self.collection_string == config.get_collection_string():
                 self.instance = {'key': self.id, 'value': config[self.id]}
             else:
                 model = self.get_model()
diff --git a/tests/unit/utils/test_collection.py b/tests/unit/utils/test_collection.py
index 9886fdba2..9867e9ee6 100644
--- a/tests/unit/utils/test_collection.py
+++ b/tests/unit/utils/test_collection.py
@@ -225,6 +225,22 @@ class TestCollectionElement(TestCase):
             collection.CollectionElement.from_values('testmodule/model', 1),
             collection.CollectionElement.from_values('testmodule/other_model', 1))
 
+    def test_config_cache_key(self):
+        """
+        Test that collection elements for config values do always use the
+        config key as cache key.
+        """
+        fake_config_instance = MagicMock()
+        fake_config_instance.get_collection_string.return_value = 'core/config'
+        fake_config_instance.key = 'test_config_key'
+
+        self.assertEqual(
+            collection.CollectionElement.from_values('core/config', 'test_config_key').get_cache_key(),
+            'core/config:test_config_key')
+        self.assertEqual(
+            collection.CollectionElement.from_instance(fake_config_instance).get_cache_key(),
+            'core/config:test_config_key')
+
 
 class TestCollection(TestCase):
     @patch('openslides.utils.collection.CollectionElement')