If I create a property in a class like:

public class User
{
    public string Id { get; set; }
    public BsonDocument UserSettings { get; set; }  
    .....
}

If the UserSettings is null when a new document is inserted then the driver actually creates a bson document with one name-value pair like that:

"userSettings" : {
    "_csharpnull" : true
},

That looks strange to me since i expected that property to be null like that:

"userSettings" : null,

Am I missing something?

Thanks,
Itzik