It happens for all of them.
I have Windows Server 2012 R2, IIS 8, with IIS pool in V4 and Pipeline Mode in Integrated
We check the we.config httphandlers and have this:
<add path="ChartImg.axd" verb="*" type="System.Web.UI.DataVisualization.Charting.ChartHttpHandler, System.Web.DataVisualization, Version=4.0.0.0, Culture=neutral, PublicKeyToken=31bf3856ad364e35" validate="false" />
<add type="DevExpress.Web.ASPxUploadControl.ASPxUploadProgressHttpHandler, DevExpress.Web.v13.1, Version=13.1.7.0, Culture=neutral, PublicKeyToken=b88d1754d700e49a" verb="GET,POST" path="ASPxUploadProgressHandlerPage.ashx" validate="false" />
<add type="DevExpress.Web.ASPxClasses.ASPxHttpHandlerModule, DevExpress.Web.v13.1, Version=13.1.7.0, Culture=neutral, PublicKeyToken=b88d1754d700e49a" verb="GET" path="DX.ashx" validate="false" />