Why doesn't Core:InvokeCommandAction work?

Question

Windows

Hello. There is such a self-written control element:

<controls:ToggleList x:Name="toggleList" Grid.Row="4" x:Uid="PublishersToggleList" Items="{Binding PublishersList}">
                	<Interactivity:Interaction.Behaviors>
                        <Core:EventTriggerBehavior EventName="SelectedItemChanged">
                			<Core:InvokeCommandAction Command="{Binding PublishersChandgedCommand}" 
                                  CommandParameter="{Binding SelectedItem, ElementName=toggleList, Mode=OneWay}"/>
                		</Core:EventTriggerBehavior>
                	</Interactivity:Interaction.Behaviors>
                </controls:ToggleList>

Linked command code:

public RelayCommand<Publisher> PublishersChandgedCommand
        {
            get
            {
                return new RelayCommand<Publisher>((arg) =>
                {
                    if (arg != null)
                    {
                        SelectByPublisher(arg);
                    }
                });
            }

Why doesn't this approach work for a collection element of a different type? For example, when I do like this:

<controls:ToggleList x:Name="toggleList" Grid.Row="4" x:Uid="PublishersToggleList" Items="{Binding AutorList}">
              <Interactivity:Interaction.Behaviors>
                     <Core:EventTriggerBehavior EventName="SelectedItemChanged">
              		<Core:InvokeCommandAction Command="{Binding AutorListChandgedCommand}" 
                              CommandParameter="{Binding SelectedItem, ElementName=toggleList, Mode=OneWay}"/>
                     </Core:EventTriggerBehavior>
                </Interactivity:Interaction.Behaviors>
</controls:ToggleList>

The command binds, but when the SelectedItemChanged event occurs, a System.InvalidCastException is thrown inside the MVVM Light in the Execute method