Looking at the call stack you have pasted, it seems that you are using WebFormsMVP. Therefore, I suspect that the cause for the error you are getting is the way MvpUserControl is implemented. As you may know the class exposes an AutoDataBind property, which by default will cause a call to DataBind on PreRenderComplete event. However, this will eventually recreate all databound controls too late in the page's lifecycle causing IScriptControl implementers to thrown the mentioned exception. Thus, could you set AutoDataBind property to false (inside UserControl's constructor) and see if this makes any difference in the observed behavior.
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