DeSerializing a class with property setter logic throws exception

[krishnan-unni]

I have this class which I am trying to serialize\deserialize:

public class MyClass
    {

        private string value;

        public string Value
        {
            get
            {
                return this.value;
            }

            set
            {
                if (value.Length != 5)
                {
                    throw new ArgumentOutOfRangeException("value", value.Length, "Expecting 6 length.");
                }

                this.value = value;
            }
        }

        public int intItem { get; set; }

        public SubClass SubClass { get; set; }
    }

    public class SubClass
    {
        public static SubClass GetInstance()
        {
            return new SubClass();
        }

        private SubClass()
        { }
        public int item { get; set; }

        public string stinngitem { get; set; }
    }

//Initialization for testing purpose:

JsonSerializer.SetDefaultResolver(Utf8Json.Resolvers.StandardResolver.AllowPrivateExcludeNull);
MyClass myclass = new MyClass(); 
myclass.SubClass = SubClass.GetInstance(); 
myclass.SubClass.item = 1;

//Serialization
Type type = myclass.GetType();
byte[]  serialized = JsonSerializer.Serialize(myclass);             //works fine

//deserialization
object instance = JsonSerializer.Deserialize<object>(serialized); //No error. This is what I would need to use
MyClass newMyclass = instance as MyClass;   //returns null. 

//Tried these too
MyClass newinstance = JsonSerializer.Deserialize<MyClass>(serialized);           //error
MyClass anotherinstance = JsonSerializer.NonGeneric.Deserialize(type, serialized);   //error

For all the deserialization operations the error I get is

System.NullReferenceException: 'Object reference not set to an instance of an object.

The reason is the Value property is null and it has a setter logic.

set
            {
                if (value.Length != 5)
                {
                    throw new ArgumentOutOfRangeException("value", value.Length, "Expecting 6 length.");
                }

                this.value = value;
            }

But I have set the AllowPrivateExcludeNull option.

When I try to deserialize with object as the type then it converts it all to a nested dictionary but lose all type information. So when cast to MyClass I get only a null.

I am able to do this just fine with JSON.NET. Is this a bug?