On Android, button background is not updated in very specific case (XF 1.3)

I've found an issue where triggers on a button style are not re-evaluating when a value changes if the button is in a listview and an item is deleted from the listview.

This occurs on Android only.

Here's a cut down sample of my style:

<Style x:Key="ButtonStyle" TargetType="Button">
    <Setter Property="BackgroundColor" Value="#F2F2F2" /><!-- gray -->
    <Setter Property="Text" Value="A" />
    <Style.Triggers>
        <Trigger Property="controls:ButtonExtensions.IsPrimary" Value="True" TargetType="Button">
            <Setter Property="BackgroundColor" Value="#FAC54A" /> <!-- orange -->
            <Setter Property="Text" Value="B" />
        </Trigger>
    </Style.Triggers>
</Style>

• These buttons are in ViewCell's within a ListView.
• The ListView is bound to an ObservableCollection
• The collection contains 2 models, the first item has "IsPrimary=false" and the second item has "IsPrimary=true"
• Delete the first item from the collection

Expected result:
The list contains one item. The button has "Text=A" and a color of orange.

Actual result
The list contains one item. The button has "Text=A" but the color is gray.

You can see that the trigger is firing, because the text is updated. But the background is not updated.

I've got a workaround by copying the existing ButtonRenderer and changing the following line of code in the OnElementPropertyChanged method of the Android renderer:

before:

if (this.drawableEnabled && (e.PropertyName == VisualElement.BackgroundColorProperty.PropertyName || e.PropertyName == Button.BorderColorProperty.PropertyName || e.PropertyName == Button.BorderRadiusProperty.PropertyName || e.PropertyName == Button.BorderWidthProperty.PropertyName)) {
    this.backgroundDrawable.Reset ();
    base.Control.Invalidate ();
}

after:

if (this.drawableEnabled && (e.PropertyName == "Renderer" || e.PropertyName == VisualElement.BackgroundColorProperty.PropertyName || e.PropertyName == Button.BorderColorProperty.PropertyName || e.PropertyName == Button.BorderRadiusProperty.PropertyName || e.PropertyName == Button.BorderWidthProperty.PropertyName)) {
    this.backgroundDrawable.Reset ();
    base.Control.Invalidate ();
}

So when the button is redrawn after ListView item is deleted, this causes the background drawable resource to be recalculated... Don't know if this is a "proper" fix or just a hack, but it's the only way I could get it to work...