If any column name contains some text enclosed by round brackets '()' then table will not be rendered

Suppose I have a json array name myEmployees as $scope.myEmployees = [{ "firstName (Employee Name)": "Cox", "lastName": "Carney", "company": "Enormo", "employed": true }, { "firstName (Employee Name)": "Lorraine", "lastName": "Wise", "company": "Comveyer", "employed": false }, { "firstName (Employee Name)": "Nancy", "lastName": "Waters", "company": "Fuelton", "employed": false }];

Here is my html. <div id="grid1" ui-grid="{ data: myEmployees }" class="grid"></div>

This code produces error and table will not be rendered. An example of this issue is here, Plunker Link