Glitch with controls inside cards

Bug explanation

It appears that there is a visual glitch whenever a certain controls are clicked on dark theme (when they're inside a card).

An example:

 <Button  Grid.Row="3"  ToolTip="Actualiser"
                                                     Width="24" Height="24"  Command="{Binding RefreshCommand}" Style="{StaticResource MaterialDesignToolForegroundButton}" >
            <materialDesign:PackIcon Visibility="{Binding ElementName=DemoItemsListBox, Path=SelectedItem.AddButton}" HorizontalAlignment="Center" VerticalAlignment="Center" Kind="Refresh"  Width="24" Height="24"></materialDesign:PackIcon>
        </Button>

Results (when inside a card):

Results (when I put the exact same code outside of the card):

Same thing with a DataGridView when it's inside the card (it's not that apparent, but you can see the glitch on the left side of the sort arrow:

This also happens with the Light theme switched ON.

What could be the problem here? I'm suspecting its the window hosting this UserControl, but I'm not sure where to start looking.
If I host these buttons on a dialog, or something, they work just fine.

Version

4.5.0

Beginne damit, das gemeldete Verhalten von Button und DataGridView innerhalb und außerhalb einer Karte mit den im Issue beschriebenen dunklen und hellen Themes zu reproduzieren. Vergleiche die visuellen Ergebnisse in Version 4.5.0; als erledigt gilt die Aufgabe, wenn Steuerelemente innerhalb von Karten in beiden Themes ohne den gemeldeten Glitch gerendert werden.