<cfscript>
function f1() {
    var data = {
      a : {
        id : 1,
        b : {
          id : 2
        }
      }
    };

    var myFunc = function() {
      writeDump(data); // looks good
      writeDump(data.a); // looks good

      writeDump(data.a.id); //shows undefined on ACF10-2016
      writeDump(data.a.b); //shows undefined on ACF10-2016
      writeDump(data.a.b.id); //shows undefined on ACF10-2016

      writeDump(data["a"]["b"]); // looks good
      writeDump(data.a["b"]); // looks good
      //writeDump(data.a.b["id"]); // error!

      writedump(serializeJSON(data)); // looks good
      writedump(structKeyArray(data.a)); // looks good
    };

    myFunc();
}

f1();

</cfscript>