Problem appers with x-axis if you try to zoom. 

Chart without zoom: https://drive.google.com/file/d/1Nem_NctJN5WtzypS8JgZTtIuAARGFQbd/view?usp=sharing

Chart with some zoom: https://drive.google.com/file/d/1TRJZX3FI52YXyuWgB_kpkMTWWXKecVC_/view?usp=sharing

Project included.

The contrast between the colors for the background and the text in the Tooltip of the Chart series is very low (dark background and black text). https://www.screencast.com/t/fhx6937j

The problem is most obvious in the Outlook, Simple, Web20 and Sunset skins. 

Workaround would be  setting the Color property for the ToolTipAppearance to White

Code that reproduces the issue:

<telerik:RadHtmlChart runat="server" ID="RadHtmlChartColumnGender" Transitions="true" Width="150" Height="300">
			<PlotArea>
				<Series>
					<telerik:ColumnSeries Name="Male" Stacked="true" StackType="Stack100">
						<SeriesItems>
							<telerik:CategorySeriesItem Y="69" />
						</SeriesItems>
					</telerik:ColumnSeries>
					<telerik:ColumnSeries Name="Female" Stacked="true" StackType="Stack100">
						<SeriesItems>
							<telerik:CategorySeriesItem Y="3" />
						</SeriesItems>
					</telerik:ColumnSeries>
				</Series>
				<YAxis NarrowRange="false"></YAxis>
			</PlotArea>

		</telerik:RadHtmlChart>

Workaround:

		<script>
			function pageLoad() {
				var kendoChart = $find("RadHtmlChartColumnGender").get_kendoWidget();
				var valueAxis = kendoChart.options.valueAxis;
				valueAxis.narrowRange = false;
				$find("RadHtmlChartColumnGender").setOptions({valueAxis: valueAxis});
			}
		</script>

If you set in code behind CharTitle with simple Quote like 
RadChart1.ChartTitle.Text = "Présences sur l'année sélectionnée";
you obtain a blank space chart (nothing display)

you have to set for running
RadChart1.ChartTitle.Text = "Présences sur l'année sélectionnée";

When you configure RadHtmlChart's YAxis with NarrowRange set to true, the setting is not serialized and as a result, not applied.
You can avoid it by setting the narrowRange on the client-side:

		<telerik:RadHtmlChart runat="server" ID="RadHtmlChart1" Width="250px" Height="300px">
			<ClientEvents OnLoad="chartLoad" />
			...
		</telerik:RadHtmlChart>
		<script>
			function chartLoad(){
				var chart = $telerik.$("#RadHtmlChart1").data("kendoChart");
				chart.options.valueAxis.narrowRange = true;
			}
		</script>

               <script>
			function chartLoad() {
				$find("RadHtmlChart2").get_kendoWidget().setOptions({
					legend: {
						position: "top",
						width: 162,
						height: 88,
						orientation: "vertical"
					}
				})
			}
		</script>
		<telerik:RadHtmlChart ID="RadHtmlChart2" runat="server" Width="350" Height="350">
			<ClientEvents OnLoad="chartLoad" />
			...
		</telerik:RadHtmlChart>

 Workaround use padding instead of margin:
		<telerik:RadHtmlChart ID="RadHtmlChart1" runat="server"  Width="600px" Height="400px">
			<PlotArea>
				<Series>
					<telerik:ColumnSeries Name="Product 1">
						<SeriesItems>
							<telerik:CategorySeriesItem Y="15000" />
							<telerik:CategorySeriesItem Y="-4000" />
							<telerik:CategorySeriesItem Y="10000" />
						</SeriesItems>
					</telerik:ColumnSeries>
				</Series>
				<XAxis>
					<LabelsAppearance RotationAngle="45">
						<TextStyle Padding="135 0 0 0" />
					</LabelsAppearance>
					<Items>
						<telerik:AxisItem LabelText="item1" />
						<telerik:AxisItem LabelText="item2" />
						<telerik:AxisItem LabelText="item3" />
					</Items>
				</XAxis>
			</PlotArea>
		</telerik:RadHtmlChart>

For the time being you can use the following JavaScript workaround:

		<telerik:RadHtmlChart ID="RadHtmlChart1" runat="server" Width="600" Height="300">
			<PlotArea>
				<Series>
					<telerik:LineSeries Name="series 1">
						<SeriesItems>
							<telerik:CategorySeriesItem Y="30" />
							<telerik:CategorySeriesItem Y="10" />
							<telerik:CategorySeriesItem Y="25" />
							<telerik:CategorySeriesItem Y="20" />
						</SeriesItems>
					</telerik:LineSeries>
				</Series>
				<XAxis MinValue="1">
				</XAxis>
			</PlotArea>
		</telerik:RadHtmlChart>
		<script>

                       //JavaScript workaround

			function isNumber(val) {
				return typeof val === "number" && !isNaN(val);
			}


			var dataviz = kendo.dataviz,
				inArray = dataviz.inArray,
				deepExtend = kendo.deepExtend,
				math = Math,
				AREA = "area",
				VERTICAL_AREA = "verticalArea",
				VERTICAL_LINE = "verticalLine",
				LINE = "line";

			kendo.dataviz.CategoricalPlotArea.fn.filterSeries = function (currentSeries, categoryAxis) {
				var range = categoryAxis.totalRangeIndices();
				var justified = categoryAxis.options.justified;
				var outOfRangePoints = inArray(currentSeries.type, [LINE, VERTICAL_LINE, AREA, VERTICAL_AREA]);
				var categoryIx;

				range.min = isNumber(categoryAxis.options.min) ? math.floor(range.min) : 0;
				range.max = isNumber(categoryAxis.options.max) ? (justified ? math.floor(range.max) + 1 : math.ceil(range.max)) : currentSeries.data.length;

				currentSeries = deepExtend({}, currentSeries);

				if (outOfRangePoints) {
					var minCategory = range.min - 1;
					var srcCategories = categoryAxis.options.srcCategories || [];
					if (minCategory >= 0 && minCategory < currentSeries.data.length) {
						categoryIx = minCategory;
						currentSeries._outOfRangeMinPoint = {
							item: currentSeries.data[categoryIx],
							category: srcCategories[categoryIx],
							categoryIx: -1
						};
					}

					if (range.max < currentSeries.data.length) {
						categoryIx = range.max;
						currentSeries._outOfRangeMaxPoint = {
							item: currentSeries.data[categoryIx],
							category: srcCategories[categoryIx],
							categoryIx: range.max - range.min
						};
					}
				}

				categoryAxis._seriesMax = math.max(categoryAxis._seriesMax || 0, currentSeries.data.length);

				currentSeries.data = (currentSeries.data || []).slice(range.min, range.max);

				return currentSeries;
			}
		</script>

For the time being the reversed properties can be set through the kendo widget:
		<script>
			function pageLoad(sender, args) {

				var radarChart = $find('<%=RadarLineChart.ClientID%>').get_kendoWidget();
				var polarChart = $find('<%=PolarAreaChart.ClientID%>').get_kendoWidget();


				radarChart.options.valueAxis.reverse = true;
				polarChart.options.yAxis.reverse = true;


				radarChart.options.categoryAxis.reverse = true;
				polarChart.options.xAxis.reverse = true;

				radarChart.redraw();
				polarChart.redraw();
			}
		</script>

		<telerik:RadHtmlChart runat="server" ID="RadarLineChart" Width="345" Height="345">
			<PlotArea>
				<XAxis Reversed="true">
					<Items>
						<telerik:AxisItem LabelText="January"></telerik:AxisItem>
						<telerik:AxisItem LabelText="February"></telerik:AxisItem>
						<telerik:AxisItem LabelText="March"></telerik:AxisItem>
						<telerik:AxisItem LabelText="April"></telerik:AxisItem>
						<telerik:AxisItem LabelText="May"></telerik:AxisItem>
					</Items>
				</XAxis>
				<YAxis Reversed="true">
				</YAxis>
				<Series>
					<telerik:RadarLineSeries Name="Avg Low" MissingValues="Gap">
						<SeriesItems>
							<telerik:CategorySeriesItem Y="1000"></telerik:CategorySeriesItem>
							<telerik:CategorySeriesItem Y="8000"></telerik:CategorySeriesItem>
							<telerik:CategorySeriesItem Y="11000"></telerik:CategorySeriesItem>
							<telerik:CategorySeriesItem Y="13000"></telerik:CategorySeriesItem>
							<telerik:CategorySeriesItem Y="12000"></telerik:CategorySeriesItem>
						</SeriesItems>
					</telerik:RadarLineSeries>
				</Series>
			</PlotArea>
		</telerik:RadHtmlChart>

		<telerik:RadHtmlChart runat="server" ID="PolarAreaChart" Width="345" Height="345">
			<PlotArea>
				<XAxis Reversed="true">
				</XAxis>
				<YAxis Reversed="true">
				</YAxis>
				<Series>
					<telerik:PolarAreaSeries Name=">12.3 knots">
						<SeriesItems>
							<telerik:PolarSeriesItem Angle="125" Radius="2.4"></telerik:PolarSeriesItem>
							<telerik:PolarSeriesItem Angle="138" Radius="7.5"></telerik:PolarSeriesItem>
							<telerik:PolarSeriesItem Angle="152" Radius="8.3"></telerik:PolarSeriesItem>
							<telerik:PolarSeriesItem Angle="166" Radius="4.3"></telerik:PolarSeriesItem>
						</SeriesItems>
					</telerik:PolarAreaSeries>
				</Series>
			</PlotArea>
		</telerik:RadHtmlChart>

JavaScript workaround:
		<telerik:RadHtmlChart runat="server" ID="LineChart" Width="800" Height="500" Transitions="true">
			<PlotArea>
				<Series>
					<telerik:LineSeries Name="Week 15" ZIndex="0">
						<SeriesItems>
							<telerik:CategorySeriesItem Y="15" />
							<telerik:CategorySeriesItem />
							<telerik:CategorySeriesItem Y="71" />
							<telerik:CategorySeriesItem Y="93" />
							<telerik:CategorySeriesItem Y="43" />
							<telerik:CategorySeriesItem Y="23" />
						</SeriesItems>
					</telerik:LineSeries>
				</Series>
			</PlotArea>
		</telerik:RadHtmlChart>
		<script>
			kendo.dataviz.LineChart.fn.animationPoints = function () {
				var series = this.seriesOptions;
				var points = [];
				var seriesPoints;
				var pointsIdx, idx;
				for (idx = 0; idx < series.length; idx++) {
					if (series[idx].markers.visible) {
						seriesPoints = this.seriesPoints[idx];
						for (pointsIdx = 0; pointsIdx < seriesPoints.length; pointsIdx++) {
							if (seriesPoints[pointsIdx] != null) {
								points.push(seriesPoints[pointsIdx].marker);
							}
						}
					}
				}
				return points.concat(this._segments);
			}
		</script>

The workaround is to convert the color names to HEX, for example through the following HexConverter() method:
ASPX:

        <telerik:RadClientExportManager runat="server" ID="RadClientExportManager1">
        </telerik:RadClientExportManager>
        <telerik:RadButton ID="RadButton1" runat="server" OnClientClicked="exportRadHtmlChart" Text="Export RadHtmlChart to PDF" AutoPostBack="false" UseSubmitBehavior="false"></telerik:RadButton>
        <telerik:RadHtmlChart ID="RadHtmlChart1" runat="server" Width="600" Height="400">
            <PlotArea>
                <Series>
                    <telerik:ColumnSeries Name="Series 1" DataFieldY="myValues" ColorField="Color">
                    </telerik:ColumnSeries>
                </Series>
            </PlotArea>
        </telerik:RadHtmlChart>
        <script>
            var $ = $telerik.$;
            function exportRadHtmlChart() {
                $find('<%=RadClientExportManager1.ClientID%>').exportPDF($(".RadHtmlChart"));
            }
        </script>

C#:

    protected void Page_Load(object sender, EventArgs e)
    {
        DataTable dt = GetData();

        for (int i = 0; i < dt.Rows.Count; i++)
        {
            //Not all Color Names can be exported
            // dt.Rows[i]["Color"] = ColorTranslator.ToHtml(GetColor(i));

            //Convert colors to HEX works properly
            dt.Rows[i]["Color"] = HexConverter(GetColor(i));
        }
        RadHtmlChart1.DataSource = dt;
        RadHtmlChart1.DataBind();
    }

    public static DataTable GetData()
    {
        DataTable dt = new DataTable("ChargeData");
        dt.Columns.Add("myValues", typeof(int));
        dt.Columns.Add("Color", typeof(string));


        dt.Rows.Add(11, "");
        dt.Rows.Add(12, "");
        dt.Rows.Add(13, "");
        dt.Rows.Add(14, "");
        dt.Rows.Add(15, "");
        dt.Rows.Add(16, "");
        dt.Rows.Add(17, "");
        dt.Rows.Add(18, "");
        dt.Rows.Add(19, "");
        dt.Rows.Add(20, "");
        return dt;
    }

    public static String HexConverter(System.Drawing.Color c)
    {
        return "#" + c.R.ToString("X2") + c.G.ToString("X2") + c.B.ToString("X2");
    }

    public static Color GetColor(int index)
    {
        return colors[index % colors.Length];
    }

    public static readonly Color[] colors =
    {
        Color.Orange,
        Color.Violet,
        Color.MediumSeaGreen,
        Color.HotPink,
        Color.Black,
        Color.DarkGoldenrod,
        Color.DarkMagenta,
        Color.Chocolate,
        Color.DarkOliveGreen,
        Color.DarkTurquoise
    };