diff --git a/src/Utility/Utility.php b/src/Utility/Utility.php
index b623c7da..8d831688 100644
--- a/src/Utility/Utility.php
+++ b/src/Utility/Utility.php
@@ -139,6 +139,7 @@ class Utility {
    */
   public static function splitPropertyPath($property_path, $separate_last = TRUE, $separator = IndexInterface::PROPERTY_PATH_SEPARATOR) {
     $function = $separate_last ? 'strrpos' : 'strpos';
+    $property_path = $property_path ?? '';
     $pos = $function($property_path, $separator);
     if ($pos !== FALSE) {
       return [