Runtime error with dynamic objects in iOS

Hi
We are using Newtonsoft to deserialize our Json string as follows
var a = Newtonsoft.Json.JsonConvert.DeserializeObject("{ Name: 'Test' }") as dynamic;

Then if I do the following:

var name = a.Name ;

i get a runtime exception - System.NotImplementedException: Interpreter of ref types

The error only happens in iOS. It works fine in Andriod. Can someone please help me fix this issue. Please note that the string we deserialize is massive and random in structure.