Axis labels dissapear

Hello. When I try to add to curve some points with very small numbers:

curve.DataSeries = chartData;
chartData.Append(1, -6.525999992441564E-04);
chartData.Append(2, -6.5259999988724722E-04);
chartData.Append(3, -6.52599999843273E-04);
chartData.Append(4, -6.5259999970558607E-04);
chartData.Append(5, -6.5259999978135147E-04);

y axis not shown labels whatever Text Formatting property for this is. What I’m doing wrong? I noticed if I add points with -3 order of value, axis labels will show.
Surface description:

<sc:SciChartSurface>
    <sc:SciChartSurface.RenderableSeries>
        <sc:FastLineRenderableSeries Name="curve"/>
    </sc:SciChartSurface.RenderableSeries>
    <sc:SciChartSurface.XAxis>
        <sc:NumericAxis/>
    </sc:SciChartSurface.XAxis>
    <sc:SciChartSurface.YAxis>
        <sc:NumericAxis TextFormatting="E3" AutoRange="Always" x:Name="yAxis"/>
    </sc:SciChartSurface.YAxis>
</sc:SciChartSurface>