fix default value on date picker field: https://www.drupal.org/project/reserve/issues/3047690

src/Form/CalendarDatePicker.php

@@ -32,7 +32,7 @@ class CalendarDatePicker extends FormBase {
       '#description' => $this->t('Click in box to select date.'),
     ];
 
-    if (count($path_args) == 5) {
+    if (count($path_args) >= 5) {
       $date = date('Y') . '-' . $path_args[4] . '-' . $path_args[5];
       $form['date']['#default_value'] = $date;
     }