I am not sure it is about mixing implementations, just that it crashes with one and not the other. One implementation runs the destructor and then sets the poi

I am not sure it is about mixing implementations, just that it crashes with one and not the other. One implementation runs the destructor and then sets the pointer to null -> when code invoked by the destructor accesses the pointer everything still works. The other implementation sets the pointer to null and then runs the destructor -> when code invoked by the destructor accesses the pointer it gets a null.