Ion-nav-buttons "Simple" navigation issue

HI All, I have a code pen ( it is a very dirty hack of an existing pen. I have replicated an issue i am getting with the back button disappearing when you press the home button twice - anyone have a similar issue. Try going to the “right button” page from the home page - it work like a charm.

Now go back to the home page. when you are on the home page - from the left menu select home page again then try and visit the “right button” page. Notice the back button has disappeared.