diff --git a/lib/internal/Magento/Framework/View/Element/AbstractBlock.php b/lib/internal/Magento/Framework/View/Element/AbstractBlock.php
index 0ffa9dce7f730..b2f857bf29f45 100644
--- a/lib/internal/Magento/Framework/View/Element/AbstractBlock.php
+++ b/lib/internal/Magento/Framework/View/Element/AbstractBlock.php
@@ -1074,7 +1074,7 @@ protected function getCacheLifetime()
 
         $cacheLifetime = $this->getData('cache_lifetime');
         if (false === $cacheLifetime || null === $cacheLifetime) {
-            return $cacheLifetime;
+            return null;
         }
 
         return (int)$cacheLifetime;