diff --git a/src/Fieldtypes/Arr.php b/src/Fieldtypes/Arr.php
index 582a55a427..67fe47f682 100644
--- a/src/Fieldtypes/Arr.php
+++ b/src/Fieldtypes/Arr.php
@@ -36,7 +36,7 @@ protected function configFieldItems(): array
 
     public function preProcess($data)
     {
-        return array_merge($this->blankKeyed(), $data ?? []);
+        return array_replace($this->blankKeyed(), $data ?? []);
     }
 
     public function preProcessConfig($data)