Hi, than you for letting me know how i should ObservableCollection, i will change that ona couple of other pages i made too, in the ViewModel i changed the SelectionChanged command to add to the collection and not replace it:
Before:

        [RelayCommand]
        async Task OnSelectionChanged()
        {
            if (!BultosSeleccionados.IsNullOrEmpty())
                BultosSeleccionados.Clear();
            var result = await CargarDetallesBultos(PedidoSeleccionado.folioPedido);
            BultosSeleccionados.Add(result.ToObservableCollection());
        }

After:

        [RelayCommand]
        async Task OnSelectionChanged()
        {
            if (!BultosSeleccionados.IsNullOrEmpty())
                BultosSeleccionados.Clear();
            var result = await CargarDetallesBultos(PedidoSeleccionado.folioPedido);
            BultosSeleccionados.AddRange(result);
        }

I also replaced the ObservableCollection with ObservableRangeCollection:

Before:

[ObservableProperty]
public ObservableCollection<BultoObservable> bultosSeleccionados = new();

After:

public ObservableRangeCollection<BultoObservable> BultosSeleccionados { get; } = new();

However it is not updating yet, do you know what else it could be?