Currently, depending on the platform, the first piece of the pie is drawn at 3 or 9 o'clock. It should be possible for the developer to set the starting point to be 12 o'clock.

Labels of the axis can get trimmed when data is updated at runtime.

Categorical series that have multiple data points in the same category do not stack correctly.

Edit: Avalable in R3 2017 SP release.

Currently the Annotation is always rendered on top of the series. Add a feature that will allow setting the series above the chart annotation. 

After setting properties like FillColor, LineColor, LineThickess, etc. they are overridden by the Chart default palette.

Available in minor release 2017.2.0602. It will also be available in the R2 2017 SP release.

Provide more control over the series rendering

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.

DateTimeContinuousAxis does not display afternoon times correctly. They appear as 'AM'

DateTimeContinuousAxis labels are off by one hour when device is in DST zone (Android).
Available in the R3 2017 release.

LineSeries.Stroke and StrokeThickness are not applied when Palette is set

It is inconsistent with Android where the lines are not present and the background is transparent.

Workaround: 

<telerikChart:RadCartesianChart.Grid>
                <telerikChart:CartesianChartGrid x:Name="grid" StripLinesVisibility="None" />
</telerikChart:RadCartesianChart.Grid>

or:

chart.Grid = new CartesianChartGrid() { StripLinesVisibility = GridLineVisibility.None };

Available in the 2018 R2 SP release.

Chart: The first label disappears when dragging over the chart on iOS

When added in page content dynamically  RadPieChart shows its original size correctly and then coerce to 200,200 size.