Have no fear, this is perfectly normal. Caller ID is actually made of three bits of information: Name, Number, and Location. How much of that is passed to imp, and then to you, depends on where someone is calling from, what phone they are using, what telephone carrier you are using, what carrier they are using, and the price of rice. Seriously. We scratch our heads on this all the time. What we do know is that imp will pass along all the information it can. And that the information may vary from call to call.