A cache-overriding reload isn't a fix-all, but it is the first thing I tell anyone to try ("Hold Shift and click the Refresh button") when they're having a problem with a web site.

In order to make the back button inside the browser reload the page with updated live cache data, you will need to add the JavaScript codes mentioned here.

@dagnelies This is expected behavior. If the access token expires, the only way for Office Online to get a new one is for the host to issue one. So the app navigates window.top to be the HostEditUrl ...