If you didn't set the s.PageName variable, Adobe will automatically take URL as the Page Name.
But that's not the right way to capture Page Name if you want URL to be in your Page Name variable.
Because URL will have different protocols (http or https), it might have domain with www. or sometimes without www., it might have different Query String Parameters, different Query String Parameter Values etc.
So I would recommend you to capture the URL properly rather than leaving it to Adobe.