Xamarin.Forms 2.0 issues

I just recompiled my project with Xamarin.Forms 2.0 and found Application.Current.SavePropertiesAsync is not working as expected in "Release" mode.

I used the following code to save the login email

Application.Current.Properties ["LoginEmail"] = loginInfo.Email;
await Application.Current.SavePropertiesAsync ();

and then load it when the app starts.
if (Application.Current.Properties.ContainsKey ("LoginEmail")) {
c_email.Text = (string)Application.Current.Properties ["LoginEmail"];
}

But now, I cannot load the saved email any more. The strange thing is, it still works in debug mode. Can anyone help me out?. It will be a big headache for me to rollout an update.

Thanks.