ContentPage & Grid Not Showing Everything

I have a ContentPage that contains a Grid defined as follows:

<Grid x:Name="grdLayout" BackgroundColor="Red" ColumnSpacing="0" RowSpacing="0">
    <Grid.RowDefinitions>
        <RowDefinition Height="Auto"/>
        <RowDefinition Height="*"/>
        <RowDefinition Height="Auto"/>
        <RowDefinition Height="Auto"/>
        <RowDefinition Height="20"/>
    </Grid.RowDefinitions>
    <Grid.ColumnDefinitions><ColumnDefinition Width="Auto"/><ColumnDefinition Width="*"/></Grid.ColumnDefinitions>
</Grid>

However, Row 2-4 do not extend the full width of the Grid, while Row 0-1 do. Here are screenshots of cells (Row 0, Column 1) & (Row 2, Column 1):


Both of these cells contain a ScrollView containing a StackLayout, which are almost identical (all properties, for the ScrollView, StackLayout, and their Children, which are Frames containing a Label). Notice that in Row 2 (and the rows after it, which is the Red area) the cell content is clipped. But the clipped area is Black, not Red (which means it is not part of the Grid). However, if I remove the 4th Frame (the Gray one) in the StackLayout in the ScrollView (for both of the ScrollViews), I get the following:


Notice that in Row 0, the area that used to be Gray (the Frame that was removed) is now Red (meaning it is part of the Grid). To me, this implies that the Grid does not have a flat right edge, but is that possible? And why does it choose the color Black (the only things on the page that use Black are text & the area you see on the left, which is in Row 1)? I am completely out of ideas. Any suggestions? Thanks.