What can cause VTable pointer to be 0xffffdffffddd in Win32 debug build?

Question

I am debugging a defect and have narrowed it down to the vtable pointer for an object being 0xffffdffffddd. This answer indicates that Win32 debug builds will gene

Answer 1

If pMyObject->someMethod() ultimately ends up modifying the myObjects list it will invalidate any of the current iterators.

Additionally if the pointer data is already deleted this will trigger the same issue.