web design breaks apart

I am having a quirky issue with a website I have created. The website consists of HTML, MYSQL, and PHP. The website looks and performs as it should on my Apple MacBook Pro and IPAD Pro using the Safari web browser. When I view the website on my Iphone 6S also using the Safari web browser it looks and performs as it should UNTIL I refresh a page, then the design breaks. The fonts get wacky and elements scatter over the page. Have you ever heard of this? Is there anything I should check or look into? Any advice is appreciated.