I have tried to reproduce to described issue but to no avail. You can find a short video with the test as well as a VS sample that I have used for the test in the attached archive and then notify me if I am missing something.
The used sample is a modified version of the example in the Client-side API
help article. You can helpful that example as well as the HtmlChart - Client-side Binding
online demo in resolving the unexpected behavior.
It may also be possible that you are using an older version of RadControls that do not support the client-side databinding functionality yet. If that is the case we strongly recommend to update your version of RadControls to the latest one. This
help article will shed more light on how to do that.
If the above information, however, is not helpful could you please amend my VS example, so that it reproduces your issue and then tell us what changes you have made, so that we can proceed further with the investigation?
the Telerik team
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