Removing an item from the ItemsSource always removes the last card in the UI, regardless of the item's index in the ItemsSource. For example, if you remove an item at index 0, the last visual element (card) will be removed instead of the first one in the view. 

To resolve the issue, you can reset the ItemsSource of the RadCardView control after the collection changed action.

var source = this.cardView.ItemsSource;
this.cardView.ItemsSource = null;
this.cardView.ItemsSource = source;