We have to load a control which has a webdatagrid dynamically at some point like below

ipc = LoadControl("../picker.ascx");

Holder.Controls.Add(ipc);

Normally it works fine. But during one of the calls, we get the below error with the below stacktrace

Invalid JSON primitive

at System.Web.Script.Serialization.JavaScriptObjectDeserializer.BasicDeserialize(String input, Int32 depthLimit, JavaScriptSerializer serializer)
at System.Web.Script.Serialization.JavaScriptSerializer.Deserialize(JavaScriptSerializer serializer, String input, Type type, Int32 depthLimit)
at System.Web.Script.Serialization.JavaScriptSerializer.DeserializeObject(String input)
at Infragistics.Web.UI.Framework.RunBot.HandleOnInit(HttpContext context)
at Infragistics.Web.UI.Framework.Data.FlatDataBoundControl.OnInit(EventArgs e)
at Infragistics.Web.UI.GridControls.WebDataGrid.OnInit(EventArgs e)
at System.Web.UI.Control.InitRecursive(Control namingContainer)
at System.Web.UI.Control.InitRecursive(Control namingContainer)
at System.Web.UI.Control.InitRecursive(Control namingContainer)
at System.Web.UI.Control.InitRecursive(Control namingContainer)
at System.Web.UI.Control.InitRecursive(Control namingContainer)
at System.Web.UI.Control.AddedControl(Control control, Int32 index)
at System.Web.UI.ControlCollection.Add(Control child)