Posted this allready v5.5.1!
5.5.2 not fixed!
When editing a page in the frontend. Choose save, exits edit mode, ok!
So go browsing your site and than using the browser back button, when the edited page called. The page is back in edit modus.
Just by using the browser back<<>>forward buttons.
Copy To Current
I have verified this bug still exists in the current version of concrete5.