Hi,
Could you try to change the code:
if(!empty($_SERVER["REDIRECT_URL"]) && preg_match('#.*index\.php$#',$_SERVER["REDIRECT_URL"]) && empty($_SERVER['QUERY_STRING'])&&(empty($_SERVER['REDIRECT_QUERY_STRING']) || strpos($_SERVER['REDIRECT_QUERY_STRING'],'&')===false) && !empty($_SERVER["REQUEST_URI"])){
to:
if(!empty($_SERVER["REDIRECT_URL"]) && preg_match('#.*index\.php$#',$_SERVER["REDIRECT_URL"]) && !empty($_SERVER["REQUEST_URI"])){
in the file administrator/components/com_hikashop/helpers/helper.php and see if that helps ?