Is it a good idea to make service calls during deserialization?

In the Newtonsoft docs for CustomCreationConverter, it says:

"A more complicated scenario could involve an object factory or service locator that resolves the object at runtime."

I'm dealing with such a scenario where I have to hydrate a persistent object with an incoming DTO (which is in JSON). To hydrate the persistent object, I have to first load it using a service call. I can make this call during deserialization using CustomCreationConverter. Or I can consume the JSON as an ExpandoObject and transitively assign all members. Complexity is not much as the object graph is small.

Something about making service calls during deserialization does not seem right. It makes testing more complicated as I would have to first load that object into memory to be able to deserialize it. This also screams tight coupling.

So my question is: Is it a good idea to make service calls during deserialization?