A page with a ListView/ ObservableCollection is throwing an ArugumentException, only on Windows Phone and only when navigating back up the stack to the page.
The exception originates as
A first chance exception of type 'System.ArgumentException' occurred in System.Windows.ni.dll
then is thrown as an unhandled exception in App.Application_UnhandledException.
It looks like this is only a problem when populating the ObservableCollection asyncronously using async/ await in OnAppearing, although the result is dispatched to the UI thread using Device.BeginInvokeOnMainThread().