diff --git a/src/EventSubscriber/ContentTypePersister.php b/src/EventSubscriber/ContentTypePersister.php
index d20811b..c34a0d2 100644
--- a/src/EventSubscriber/ContentTypePersister.php
+++ b/src/EventSubscriber/ContentTypePersister.php
@@ -86,7 +86,9 @@ private function setContentFields(Content $content, Form $form, PostSubmitEvent
             }
 
             if (is_array($value)) {
-                $value = implode(', ', $value);
+                $value = implode(', ', array_map(function ($entry) {
+                  return $entry[0];
+                }, $value));
             }
             $value = (string) $value;