It's not like that on my 4.2.2 site at all. When I go to
www.site.com, it shows the CMS but the url stays at
www.site.com. However, if I later click around and then click on the Home tab, it goes to
www.site.com/content.php
What is set in AdminCP > Settings > Options > Content Management > Default Page and Site Tab URL? And what is entered as the tab URL in the Navigation Manager?