When I navigate back to the Map Fragment after having navigated away from the Map Fragment and back to it, the screen is blank or white with an esri logo. Not sure what the actual issue is as everything loads the same.
Is the MapFragment handling the onPause and onResume correctly with regards to MapView ?
Here is one sample that navigates away from map (i.e opens new PopupFragment) and returns back, except that map view is in an activity in this sample. May be you can modify one of our samples and provide the code to show what exactly is happening in your app.