I recently upgraded to the new Xamarin for Visual Studio, and since then, I can no longer hit breakpoints during IOS debugging. Android works fine, strangely.
Xamarin forms: Make sure that your view is bound with the binding context otherwise breakpoints will not hit. And the breakpoints appear as symbols not loaded.
Example :
public ExamplePage()
{
InitializeComponent();
BindingContext = App.Resolve();
}