diff --git a/app/Http/Controllers/Fo/ProductController.php b/app/Http/Controllers/Fo/ProductController.php
index 70ef51f8..9ff5fe89 100644
--- a/app/Http/Controllers/Fo/ProductController.php
+++ b/app/Http/Controllers/Fo/ProductController.php
@@ -571,10 +571,10 @@ class ProductController extends Controller
      * Delete the "sub" start filter to avoid "subsubrange" when user has some filters
      * and hard visit a total different product filter
      *
-     * @param string $filter
+     * @param string|null $filter
      * @return mixed
      */
-    private function cleanSubSubFilter(string $filter): mixed
+    private function cleanSubSubFilter(string|null $filter = null): mixed
     {
         return str_starts_with($filter, "sub") ? preg_replace('/^sub/', '', $filter) : $filter;
     }