UWP - x:Bind Mode=TwoWay throws errors without converter

There was a similar question to this, but the answer seemed to be off-base to the original question.

I've got a DataTemplate that has 3 comboboxes in it. The first two work fine, but the 3rd throws a compiler error.

<ComboBox ItemsSource="{x:Bind ListOne, Mode=OneWay}" 
              SelectedItem="{Binding SelectedOne, Mode=TwoWay}"
              DisplayMemberPath="Name"/>
<ComboBox ItemsSource="{x:Bind ListTwo}" 
              SelectedItem="{x:Bind SelectedTwo, Mode=TwoWay, Converter={StaticResource GenericConverter}}"
              DisplayMemberPath="Name"/>
<ComboBox ItemsSource="{x:Bind ListThree}" 
              SelectedItem="{x:Bind SelectedThree, Mode=TwoWay}"
              DisplayMemberPath="Name"/>

For ListOne, the "Binding" works perfectly as is.

For ListTwo, the "x: Bind" only works if a value converter is added. The "GenericConverter" only returns the "value" passed in. Other than that, it does nothing.

For ListThree, without a value converter, the compiler throws an error:

"Invalid binding path 'SelectedThree': Cannot bind type 'IdNameVm' to 'SystemObject' without a converter.

In all cases, the ItemSource is an ObservableCollection and the selected items are of type IdNameVm.

Using the converter works, but it feels wrong to be forced to put in a dummy converter on x: Bind just to get the XAML to compile.

As requested, here is how the ObservableCollection is defined plus the IdNameVm:

public ObservableCollection<IdNameVm> ListOne { get; set; }


public class IdNameVm : BindableBase
{
    private int _id;
    private string _name;

    public int Id
    {
        get { return _id; }
        set { Set(ref _id, value); }
    }

    public string Name
    {
        get { return _name; }
        set { Set(ref _name, value); }
    }

    protected bool Equals(IdNameVm other)
    {
        return Id == other.Id;
    }

    public override bool Equals(object obj)
    {
        if (ReferenceEquals(null, obj)) return false;
        if (ReferenceEquals(this, obj)) return true;
        if (obj.GetType() != this.GetType()) return false;
        return Equals((IdNameVm)obj);
    }

    public override int GetHashCode()
    {
        unchecked
        {
            var hashCode = Id;
            return hashCode;
        }
    }
}