Null reference exception when removing event handlers

Dear TypeMock Team,

I am experiencing a problem when I try to use "ExpectRemoveEvent" method on my mocked object, but the event handler was not added yet.

Please see below. The example I prepared to show this problem is very simple, it consist of a simple class:

   public class ClassB {
      public event Action<string> StatusChanged;

      void SingalStatusChanged() {
         if (StatusChanged != null) {
            StatusChanged("Changed");
         }
      }
   }

And a class that utilizes ClassB object:

   public class ClassA {
      ClassB _myObject;

      public ClassA(ClassB myObject) {
         _myObject = myObject;
      }

      public void Initialize(ClassB myObject) {
         Dispose();
         _myObject = myObject;
         _myObject.StatusChanged += _classBObject_StatusChanged;
      }

      void Dispose() {
         if (_myObject != null) {
            _myObject.StatusChanged -= _classBObject_StatusChanged;
            _myObject = null;
         }
      }

      void _classBObject_StatusChanged(string obj) {
      }
   }

The class below ( ClassA ) was especially prepared to show the problem I am seeing.

And now the test:

   [TestFixture]
   public class TestClassA {
      ClassA _classAObject;
      Mock<ClassB> _myObjectMock;

      [SetUp]
      public void SetUp() {
         _myObjectMock = MockManager.MockObject<ClassB>();
         _classAObject = new ClassA(_myObjectMock.MockedInstance);
      }

      [Test]
      public void TestInitialize() {
         _myObjectMock.ExpectRemoveEvent("StatusChanged");
         _myObjectMock.ExpectAddEvent("StatusChanged");

         _classAObject.Initialize(_myObjectMock.MockedInstance);
      }

      [TearDown]
      public void TearDown() {
         _classAObject = null;
      }
   }

When the test is run a null reference exception occurs in the line of the code, where the EventHandler is removed ( ClassA, Disppose method ) :

_myObject.StatusChanged -= _classBObject_StatusChanged;

I do not exactly understand why this is happening. I am not getting any exception when I call the Initialize method:

   class Program {
      static void Main(string[] args) {
         
         ClassA classAObject = new ClassA(new ClassB());

         classAObject.Initialize(new ClassB());
      }
   }

Which means such operation is allowed.

There is a workaround for this problem I have managed to figure out:

      [Test]
      public void TestInitialize() {
         //here is the workaround
         _myObjectMock.ExpectAddEvent("StatusChanged");
         _myObjectMock.MockedInstance.StatusChanged += MockedInstance_StatusChanged;
         //

         _myObjectMock.ExpectRemoveEvent("StatusChanged");
         _myObjectMock.ExpectAddEvent("StatusChanged");

         _classAObject.Initialize(_myObjectMock.MockedInstance);
      }

      void MockedInstance_StatusChanged(string obj) {
      }

However this is not a solution that satisifes our needs - the code we are testing is really complex and causes that a lot of redundant code is added to the tests.

Could You please help?