Isolated.WhenCalled On new Keyword Disturbs Base Variable

I think the Isolated.WhenCalled On new Keyword should not Disturb Base Variable. Here's the production code:

    public abstract class BaseClass
    {

        public int Version
        {
            get
            {

                return 1;
            }

        }

        public string FixString
        {
            get;
            set;
        }

        public BaseClass()
        {
            FixString = "hello";
        }

        public virtual int GetBaseVersion()
        {
            return Version;
        }
    }


    public class DeriveClass: BaseClass
    {

        public new int Version
        {
            get
            {

                return 2;
            }

        }
    }

And here's the test code:

        [Test]
        public void CompareAllTheVersion()
        {
            DeriveClass cdes = new DeriveClass();
            Assert.AreEqual(2, cdes.Version);
            Assert.AreEqual(1, cdes.GetBaseVersion());
        }

        [Test]
        public void CompareAllTheVersion_IsolatedThing()
        {
            DeriveClass cdes = new DeriveClass();
            Isolate.WhenCalled(()=>cdes.Version)
                .WillReturn(3);
            Assert.AreEqual(3, cdes.Version);
            Assert.AreEqual(1, cdes.GetBaseVersion());
        }

The first test passes, but the second failed because cdes.GetBaseVersion() now also returns 3. But it should return 1, because

Isolate.WhenCalled(()=>cdes.Version)
                .WillReturn(3); 

should only affect the derived class one, not the base class one.
________
Asthma advice