We believe that this is working as expected. The idea is to have two lists with the same data, but not duplicate the actual data. This could be worked around by duplicating the individual items and then adding them to a new list. However, we realize that might be clumsy. I have added a case to add a feature to allow for the duplication of a list, and all of the items within a list in one user-step. I am not sure what release it will get in to, but it is now on our radar.
