Update to Drupal 8.1.5. For more information, see https://www.drupal.org/project/drupal/releases/8.1.5

core/modules/contact/src/ContactFormInterface.php

@@ -21,7 +21,7 @@ interface ContactFormInterface extends ConfigEntityInterface {
    * Returns an auto-reply message to send to the message author.
    *
    * @return string
-   *  An auto-reply message
+   *   An auto-reply message
    */
   public function getReply();
 

core/modules/contact/src/Plugin/migrate/source/ContactCategory.php

@@ -29,7 +29,7 @@ class ContactCategory extends DrupalSqlBase {
         'selected',
       )
     );
-    $query->orderBy('cid');
+    $query->orderBy('c.cid');
     return $query;
   }
 

core/modules/contact/src/Plugin/migrate/source/ContactSettings.php

@@ -18,7 +18,7 @@ class ContactSettings extends Variable {
   protected function initializeIterator() {
     $default_category = $this->select('contact', 'c')
       ->fields('c', ['cid'])
-      ->condition('selected', 1)
+      ->condition('c.selected', 1)
       ->execute()
       ->fetchField();
     return new \ArrayIterator([$this->values() + ['default_category' => $default_category]]);