The issue is present in a quite specific setup where а CartesianChartGrid is placed within the first column of the following Grid element:
 <Grid BackgroundColor="Red">

        <Grid.ColumnDefinitions>
            <ColumnDefinition Width="15*" />
            <ColumnDefinition Width="10*" />
        </Grid.ColumnDefinitions>

If you change the proportions to "150*" and "101*" the issue is not present anymore.