Please note that combining server-side and client-side binding is not supported.
For your requirement you could get reference to the client-side object of your grid and call the master table view "rebind()" method:
var grid = $find("<%=RadGrid1.ClientID%>");
I have tested this on my end with stripped version of your code and everything is working as expected. For your convenience I am attaching the sample page.
Hope that helps.
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