样式范围问题

我有几个文本块,绑定到不同的东西。两个文本块应用了相同的样式。在样式中有一个eventtrigger,当绑定值更新时,它会闪烁文本。但是当一个textblock的值更新时,两个textblocks都会闪烁。我以为只有一个文本块会闪现。有什么想法吗?

    <Style x:Key="flashingTextBlock" TargetType="TextBlock">
        <Setter Property="Background" Value="Transparent" />
        <Setter Property="Foreground" Value="#333333" />
        <Style.Triggers>
            <EventTrigger RoutedEvent="Binding.TargetUpdated">
                <BeginStoryboard>
                    <Storyboard>
                        <ColorAnimation     
                                Storyboard.TargetProperty="(TextBlock.Foreground).(SolidColorBrush.Color)"
                                To="Orange"              
                                Duration="0:0:1"
                                AutoReverse="True"/>
                    </Storyboard>
                </BeginStoryboard>
            </EventTrigger>
        </Style.Triggers>
    </Style>

<TextBlock Text="{Binding Path=PcName, NotifyOnTargetUpdated=True}" 
        Style="{StaticResource flashingTextBlock}"/>
<TextBlock Text="{Binding Path=Time, NotifyOnTargetUpdated=True}" 
        Style="{StaticResource flashingTextBlock}"/>