ListView.Behaviors and Prism DelegateCommand problems

After hours of searching and trying I couldn't get the following to work.

Expected behavior: Tap on a item in a list once, navigate to a page. Tap 2-3 times (or more) on the same item quickly, still open ONE page and not more.

I have managed to do this, but when using a generic DelegateCommand it just won't work for some reason. I'm using Xamarin.Forms (version 3.1.0.637273) and Prism (version 7.1.0.172-pre).

In my XAML I have a ListView with the following behavior and bindings:

    <ListView 
         CachingStrategy="RecycleElement"
         ItemsSource="{Binding MyCollection}">
         <ListView.Behaviors>
              <b:EventToCommandBehavior
                   Command="{Binding MyCommand}"
                   EventName="ItemTapped"
                   EventArgsParameterPath="Item" />
         </ListView.Behaviors>
             <ListView.ItemTemplate>
                  <DataTemplate>
                       <ViewCell>
                           ...
                       </ViewCell>
                  </DataTemplate>
             </ListView.ItemTemplate>
    </ListView>

In my ViewModel I have:

    private ObservableCollection<SomeModel> _myCollection;
    public ObservableCollection<SomeModel> MyCollection
    {
        get { return _myCollection; }
        set { SetProperty(ref _myCollection, value); }
    }

    private bool _canNavigate;
    public bool CanNavigate
    {
         get { return _canNavigate; }
         set { SetProperty(ref _canNavigate, value); }
    }


    private DelegateCommand<SomeModel> _myCommand;
    public DelegateCommand<SomeModel> MyCommand =>
                _someModel ?? (_myCommand = new DelegateCommand<SomeModel>(ExecuteMethod, (parameter) => CanNavigate))
                .ObservesProperty(() => CanNavigate);

    private async void ExecuteMethod(SomeModel parameter)
    {
         CanNavigate = false;

         NavigationParameters parameters = new NavigationParameters($"?id={parameter.Id}");
         await NavigationService.NavigateAsync("SomeCoolPage", parameters);

         CanNavigate = true;
    }

I have also tried other varients with like this for example with no luck:

    private async void ExecuteMethod(SomeModel parameter)
    {
         if(CanNavigate)
         {
              CanNavigate = false;
              ...
              ...
              CanNavigate = true;
         }
    }

This code works when I'm not using the generic version of the DelegateCommand.

If anyone can point me to what is it I'm doing wrong that would be awesome. Thanks.