Not work for me using Firefox v54. I did a web search: https://www.bing.com/search?q=ozpt.com Some of the links work. https://ozpt.com/maitland-overview/ https://ozpt.com/course-descriptions/course-schedule/ Some don't.

jQuery(document).ready (function($){
   
    //Web Pre Loader
    var preloader = $('.preloader');
    $(window).load(function(){
    	preloader.remove();
    });

body > div.preloader { display: none !important; }

Your theme shows the flipping hourglass overlay in front of the page until it detects that loading has completed, and then it removes it. You can see the code in this file: https://ozpt.com/wp-content/themes/enlighten-pro/js/custom.js?ver=5.6.1 jQuery(document).ready (function($){ //Web Pre Loader var preloader = $('.preloader'); $(window).load(function(){ preloader.remove(); }); But apparently this code does not run every time you display the page, probably related to caching, similar to the problem with another theme recently: https://support.mozilla.org/questions/1320526 Could I suggest you just get rid of this kind-of-useless feature? You can prevent the preloader from displaying using some custom CSS: body > div.preloader { display: none !important; } You can add that using the "Additional CSS" option in the Theme Customizer. More info in this article (something that popped up in a web search): https://wpengine.com/resources/customize-theme-css/ If you want to keep the hourglass, check with the theme author for whether they have a solution.