When is this necessary?
Cause. The browser temporarily stores pages you have viewed in cache memory. The browser retrieves the page from cache memory and displays the saved (old) version.
Solution? You can "force" the browser to retrieve the latest version from the server by clearing the cache. Clearing all cache files will show you the current information again.
A cookie is a small text and number file that is stored in your browser or on your computer's hard disk. Cookies contain information to remember your preferences when using a website or are used to collect info about visitors. Nowadays, websites are required to ask your permission to place a cookie on your computer and to give you information about the content of this cookie.
After visiting a site, you can choose to delete cookies from your computer.
As you browse the web, your browser remembers data for you: websites you have visited, files you have downloaded, and more. All this data constitutes your "history". If you use a public computer or share a computer with someone, you may not want others to see this data.
View and delete browser history in Microsoft Edge
Clear cookies and site data in Firefox