MVC form dropdownlist click jQuery.parseJSON error

MVC form dropdownlist click jQuery.parseJSON error

I have an MVC form containing three dropdowns
@Html.DropDownListFor(item=>item.SourceId, Model.SourceList,"Pick a Source")
@Html.DropDownListFor(item=>item.Index, Model.IndexList,"Pick an Index")
@Html.DropDownListFor(item=>item.User, Model.UserList,"Pick a User")

Clicking the any one first works as expected, but clicking a second causes a jQuery.parseJSON runtime error invalid character in jquery-1.11.1.js while debugging in Visual Studio 2010 Professional. If I continue from the debug popup, the list shows up and I am able to select an entry. Oddly, clicking elsewhere in the form also causes the error after the first successful click.

I am using DataTables 1.10.2 and jQuery 1.11.1

Thanks
Ray