Normal
On the note of rattling, mine does it too so I got the idea to cut to size and stick these adhesive foam strips I have in the cutouts on the shell. It took some patients in getting the size of the strips right and the placement but it works! It's a great non-permanent non-destructive mod to fix the rattling. You could also shove paper towel or tissue paper in the cutouts too and that would probably work.
