Visual Design of MasterDetailPage

I'm noticing that on iOS the MasterDetailPage looks different than I'd expect on small form factor. It appears that the page I've set to be the Detail hangs over a bit on the right hand side of the screen. Has it always been like this? (see attached screenshot)

Is there a way to change this behavior? On small form factor, I'd like the master and detail pages to take up the entire view when navigated to.

Here's the code I have to set up the MainPage of the app:

public class MainPage : MasterDetailPage
{
    public MainPage()
    {
        Master = new NavigationPage(new ProjectList()) { Title = "Projects" };
        Detail = new NavigationPage(new ProjectDetails()) { };
        // Choose how to display the split view based on the device form factor
        if (Device.Idiom == TargetIdiom.Tablet)
        {
            MasterBehavior = MasterBehavior.Split;   // always show master/detail view on Tablets
        }
        else if (Device.Idiom == TargetIdiom.Phone)
        {
            MasterBehavior = MasterBehavior.SplitOnLandscape;  // show master/detail view on Phones in landscape orientation only
        }
        // Show Master Pane by default (Project List page)
        IsPresented = true; 
    }
}

I've tried removing the "else if" case, where I set the MasterBehavior from small form factor (phone), but the visual appearance is the same.