strtotime() expects parameter 1 to be string, int ...security/Model/AdminSessionsManager.php(338)

TypeError: strtotime() expects parameter 1 to be string, int given
#28 /var/www/share/meevo.io/releases/66/vendor/magento/module-security/Model/AdminSessionsManager.php(338):

Author: kanhaiya5590

app/code/Magento/Security/Model/AdminSessionsManager.php

@@ -335,7 +335,11 @@ protected function createAdminSessionInfoCollection()
      */
     private function lastProlongIsOldEnough()
     {
-        $lastProlongTimestamp = strtotime($this->getCurrentSession()->getUpdatedAt());
+        $lastUpdatedTime = $this->getCurrentSession()->getUpdatedAt();
+        if($lastUpdatedTime === null || is_numeric($lastUpdatedTime)) {
+            $lastUpdatedTime = "now";
+        }
+        $lastProlongTimestamp = strtotime($lastUpdatedTime);
         $nowTimestamp = $this->authSession->getUpdatedAt();
 
         $diff = $nowTimestamp - $lastProlongTimestamp;