Exclude URL option not working

Have recently installed Lite cache on a test site where I’m trying to figure out how to exclude certain pages from being cached. The pages all contain the URL string /ferns-in-britain-and-ireland, which is what I’ve put in the “URLs to exclude from cache” setting. But it has no effect as far as I can tell. Looks like they are still being cached. There’s a long string at the end of the source code starting </script><!–wp_footer–><script>function lc_get_cookie(name)… and ending with the date and time last cached. Essentially the same code appears on all pages irrespective of whether they are in the exclusion list or not. Am I doing something wrong?
Thanks