In both cases, those are the browser supplying a resource representation, while still technically being on the resource specified in the navigation bar. The thing you're seeing is an overridden representation of the server's response. (Which, in this case, just happened to be "no response.")
It's almost exactly the same as how the server sending a 304 gets the browser to load the document from cache. The server's actual response was a 304; but the browser's representation of that response is the cached HTML DOM it had laying around from the last 2xx resource-representation it received "about" the same resource.