MAGETWO-47770: Category page triggers about 800 DB requests on calls without FPC

app/code/Magento/Theme/Block/Html/Topmenu.php

@@ -49,7 +49,6 @@ class Topmenu extends Template implements IdentityInterface
         TreeFactory $treeFactory,
         array $data = []
     ) {
-        $this->setCacheLifetime(30 * 60);
         parent::__construct($context, $data);
         $this->_menu = $nodeFactory->create(
             [
@@ -60,6 +59,16 @@ class Topmenu extends Template implements IdentityInterface
         );
     }
 
+    /**
+     * Get block cache life time
+     *
+     * @return int
+     */
+    protected function getCacheLifetime()
+    {
+        return parent::getCacheLifetime() ?: 3600;
+    }
+
     /**
      * Get top menu html
      *