diff --git a/src/Bundle/ChillActivityBundle/Form/ActivityType.php b/src/Bundle/ChillActivityBundle/Form/ActivityType.php
index 19d53c262..5ef08832d 100644
--- a/src/Bundle/ChillActivityBundle/Form/ActivityType.php
+++ b/src/Bundle/ChillActivityBundle/Form/ActivityType.php
@@ -313,7 +313,7 @@ class ActivityType extends AbstractType
                         }
                         return $location->getId();
                     },
-                    function (?string $id): Location {
+                    function (?string $id): ?Location {
                         return $this->om->getRepository(Location::class)->findOneBy(['id' => (int) $id]);
                     }
                 ))