Update to Drupal 8.2.6. For more information, see https://www.drupal.org/project/drupal/releases/8.2.6

core/modules/config/tests/config_test/config/schema/config_test.schema.yml

@@ -33,6 +33,12 @@ config_test.dynamic.*.*:
   type: config_test_dynamic
   label: 'Config test dynamic settings'
 
+config_test.dynamic.*.third_party.node:
+  type: mapping
+  mapping:
+    foo:
+      type: string
+
 config_test.query.*:
   type: config_entity
   mapping:

core/modules/config/tests/config_test/src/Entity/ConfigTest.php

@@ -136,6 +136,10 @@ class ConfigTest extends ConfigEntityBase implements ConfigTestInterface {
         }
       }
     }
+    // If any of the dependencies removed still exists, return FALSE.
+    if (array_intersect_key(array_flip($this->dependencies['enforced']['config']), $dependencies['config'])) {
+      return FALSE;
+    }
     return $changed;
   }