RadChart is rendered as an ordinary image, which is served by its own HttpHandler when requested. So the issue does not seem to come from the control as long as it works correctly in Firefox. The situation here looks quite specific, we have never received such report before. It is possible that you have hit some security restrictions within some of the browsers when it comes to cross-domain requests. You can try it with less restrictive security and privacy browser settings. You can also create your own custom HttpHandler and deploy it to see whether it will work correctly under the same conditions. Once you get the configuration for it, you should get the chart working too.
As for the assembly version -- you can right-click the .dll file, choose "Properties", go to "Details" tab and check the file version.
the Telerik team