diff --git a/src/Extensions/Subsites/IndexConfigurationExtension.php b/src/Extensions/Subsites/IndexConfigurationExtension.php
index 9da94b6..5bd24ef 100644
--- a/src/Extensions/Subsites/IndexConfigurationExtension.php
+++ b/src/Extensions/Subsites/IndexConfigurationExtension.php
@@ -16,12 +16,11 @@ public function updateIndexesForDocument(DocumentInterface $doc, array &$indexes
             return;
         }
 
-        $docSubsiteId = $doc->getDataObject()->SubsiteID ?? 0;
-
-        if ((int) $docSubsiteId === 0) {
+        // Which whether the data object has the SubsiteID
+        if (!$doc->getDataObject()->hasField('SubsiteID')) {
             $this->updateDocumentWithoutSubsite($doc, $indexes);
         } else {
-            $this->updateDocumentWithSubsite($indexes, $docSubsiteId);
+            $this->updateDocumentWithSubsite($indexes, (int)$doc->getDataObject()->SubsiteID);
         }
     }