Web browsers are designed to download web pages and store them (or at least parts of them) locally on your computer's hard drive. Place in memory where the browsing data is stored is called "cache".
Why does it have to be stored at all? Browser cache records every item you have viewed or downloaded while surfing on the Internet. When you visit (refresh) the same page again, the browser uses that stored data to shorten the page loading time. Web page is being loaded from local cache instead of downloading everything from the server again. This is common browser functionality to give users better surfing experience.
When coming back to the web page you browsed previously, some elements may change and because of that, the web page may not load properly. Even after refreshing the page, something still may look broken.
KEEP CALM! There is nothing wrong with your web page.