Repair duplicating sequential numbered Compositions

Try this in After Effects CC 2014:

Make a Composition and name it 'Composition-1'.
Select it, and press cmd-D (Mac).
This results in:
Composition-1
Composition-2

Press cmd-D more to make 6 total:

Composition-1
Composition-2
Composition-3
Composition-4
Composition-5
Composition-6

Now put these in a folder named 'Folder 1',
and duplicate this folder:

Folder 1
  Composition-1
  Composition-2
  Composition-3
  Composition-4
  Composition-5
  Composition-6

Folder 2
  Composition-1
  Composition-2
  Composition-3
  Composition-4
  Composition-5
  Composition-6

Delete 2-6 from Folder 2:

Folder 1
  Composition-1
  Composition-2
  Composition-3
  Composition-4
  Composition-5
  Composition-6

Folder 2
  Composition-1
 
And now duplicate Folder 2's Composition-1 and see what happens:

Folder 1
  Composition-1
  Composition-2
  Composition-3
  Composition-4
  Composition-5
  Composition-6

Folder 2
  Composition-1
  Composition-7
  Composition-8
  Composition-9
  Composition-10
  Composition-11


Strange!

Something else:
Delete Folder 2.
Select all Compositions in Folder 1 and press cmd-D, and see the numbering.

Folder 1
  Composition-1
  Composition-2
  Composition-3
  Composition-4
  Composition-5
  Composition-6
  Composition-7
  Composition-7
  Composition-8
  Composition-8
  Composition-9
  Composition-9

Strange 2!