I have added members to a group in People, then saved the group.  The new number of contacts in the group reflects the fact that they have ben added.  But the next time I look at this group, these new members are no longer there.  I have been through this several times, following all the steps for adding members to a group - each time they appear to have been added, but the next time I want to use the group, they are missing.  Is this a bug or am I doing something wrong?