SetBinding works on Android and iOS simulator but NOT on iOS device

I have been struggling with this problem for a couple of days now. I have tried everything i could think of to solve it but nothing seems to work. I have some entries and labels that are binded to a viewmodel. Whenever i run the application on Android or on the iOS simulator everything works great but when i run it on my iOS device all the binded properties are null in the viewmodel.
Is this some kind of bug or am i missing something?

Username = new Entry 
            { 
                TextColor = Color.Black,
                Placeholder = "Username",
                WidthRequest = 250,
                HorizontalOptions = LayoutOptions.Start,
            };
            Username.SetBinding(Entry.TextProperty, "UsernameEntryText", BindingMode.TwoWay);