半透明颜色的动画有奇怪的效果

我正在做一些简单的动画,当我注意到一个奇怪的效果时,移动鼠标在一个按钮上。背景的颜色似乎变暗了,然后又变亮了,但动画代码并没有让它这样做。下面是代码的精简版本,演示了这种奇怪的效果:

<Window x:Class="WpfApp1.MainWindow"
    xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
    xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
    xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
    xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
    mc:Ignorable="d"
    Title="MainWindow" Height="950" Width="800">
    <Window.Resources>
        <Style TargetType="{x:Type Button}">
            <Setter Property="Padding" Value="16,3,16,5" />
            <Setter Property="Template">
                <Setter.Value>
                    <ControlTemplate TargetType="{x:Type Button}">
                        <Border Name="Border" Background="White" BorderBrush="#33323232" Height="{TemplateBinding Height}" MinWidth="{TemplateBinding MinWidth}" BorderThickness="2" Padding="{TemplateBinding Padding}" SnapsToDevicePixels="True">
                            <ContentPresenter Name="ContentPresenter" ContentSource="Content" TextElement.FontSize="14" HorizontalAlignment="Center" VerticalAlignment="Center" />
                        </Border>
                        <ControlTemplate.Triggers>
                            <Trigger Property="IsMouseOver" Value="True">
                                <Trigger.EnterActions>
                                    <BeginStoryboard>
                                        <Storyboard DecelerationRatio="0.75">
                                            <ColorAnimation Storyboard.TargetName="Border" Storyboard.TargetProperty="Background.Color" BeginTime="0:0:0" Duration="0:0:2" To="#1A323232" />
                                        </Storyboard>
                                    </BeginStoryboard>
                                </Trigger.EnterActions>
                                <Trigger.ExitActions>
                                    <BeginStoryboard>
                                        <Storyboard DecelerationRatio="0.75">
                                            <ColorAnimation Storyboard.TargetName="Border" Storyboard.TargetProperty="Background.Color" BeginTime="0:0:0" Duration="0:0:2" From="#1A323232" />
                                        </Storyboard>
                                    </BeginStoryboard>
                                </Trigger.ExitActions>
                            </Trigger>
                        </ControlTemplate.Triggers>
                    </ControlTemplate>
                </Setter.Value>
            </Setter>
        </Style>
    </Window.Resources>
    <Button HorizontalAlignment="Center" VerticalAlignment="Center" Width="120" Height="32" Content="Click me" />
</Window>

请注意,在本例中,我将动画的速度减慢,以使这个奇怪的效果更清晰。在实验之后,我发现如果我使用较深的颜色来设置动画,那么动画将直接转到该颜色(正常工作)。我还注意到,如果我将alpha通道设置为1(FF),问题也会消失。尝试用以下两个替换上面示例中的动画:

<ColorAnimation Storyboard.TargetName="Border" 
    Storyboard.TargetProperty="Background.Color"
    BeginTime="0:0:0" Duration="0:0:2" To="#EAEAEA" />

...

<ColorAnimation Storyboard.TargetName="Border" 
    Storyboard.TargetProperty="Background.Color" 
    BeginTime="0:0:0" Duration="0:0:2" From="#EAEAEA" />

现在,您应该看到预期的效果。这是我最后不得不做的,但我真的想用半透明的颜色代替。所以,我的问题是 ?