NativeScript: why nativescript android elevation is just working on corners in nativescript?

Question

Why android elevation is just working on corners in below image:

Link of my screenshot

<ScrollView orientation="vertical">
    <GridLayout class="viewed" rows="auto"
        columns="auto,auto" >
        <Label horizontalAlignment="center"
            class="viewed-label" text="Viewed Stories" style="android-elevation:25;">
        </Label>
    </GridLayout>
</ScrollView>

//below is css:

 .viewed{
      background-color: white;
      border-radius: 60px 60px 0px 0px;
      padding-bottom: 80px;
      margin-top: 20px;
      margin-left: 20px;
      margin-right: 20px;
      height: 100%;
      android-elevation:15;

  }