copy numbering

I really like the new copy numbering, but I've created a duplicate group that when duplicated doesn't get numbered correctly. I have Group 1, Group 2, and Group 3. When I duplicate Group 1, I get the new and appropriate Group 1 copy. If I do the same for Group 2, I also get Group 2 copy. But if I copy Group 3, I get Group 3 copy 4. There are no other Group 3 copies.