When the VerticalItemSpacing is greater than 1 and an ItemStyle with a Border is defined the background of the item is overlapping the border.

             <telerik:RadListView Grid.Column="0" ItemsSource="{Binding Source}">

                <telerik:RadListView.LayoutDefinition>

                    <telerik:ListViewLinearLayout Orientation="Vertical" VerticalItemSpacing="4" />

                </telerik:RadListView.LayoutDefinition>

                <telerik:RadListView.ItemStyle>

                    <telerik:ListViewItemStyle

                        BackgroundColor="Green"

                        BorderColor="LightGreen"

                        BorderLocation="All"

                        BorderWidth="1" />

                </telerik:RadListView.ItemStyle>

                <telerik:RadListView.SelectedItemStyle>

                    <telerik:ListViewItemStyle

                        BackgroundColor="Orange"

                        BorderColor="OrangeRed"

                        BorderLocation="All"

                        BorderWidth="1" />

                </telerik:RadListView.SelectedItemStyle>

                <telerik:RadListView.PressedItemStyle>

                    <telerik:ListViewItemStyle

                        BackgroundColor="Orange"

                        BorderColor="OrangeRed"

                        BorderLocation="All"

                        BorderWidth="1" />

                </telerik:RadListView.PressedItemStyle>

                <telerik:RadListView.ItemTemplate>

                    <DataTemplate x:DataType="local:SourceItem">

                        <telerik:ListViewTemplateCell>

                            <telerik:ListViewTemplateCell.View>

                                <Grid>

                                    <Label Margin="10" Text="{Binding Name}" />

                                </Grid>

                            </telerik:ListViewTemplateCell.View>

                        </telerik:ListViewTemplateCell>

                    </DataTemplate>

                </telerik:RadListView.ItemTemplate>

            </telerik:RadListView>