[llcj]

FWIW, if anyone is keeping track of these things, the following is what happened to me regarding duplicate shelves:

I synced and thus updated to firmware 2.4 on Feb.21, 2013 (my last previous sync was mid-November 2012, both syncs were via desktop) and ended up with duplicate shelves that behaved in the way that Corpesgodess described. I logged off on the device and synced it (over wifi.) This changed nothing. The duplicates remained and behaved as they had before logging off. I then did a factory reset. I also uninstalled the desktop app and reinstalled it before I connected my device to sync it. Synced my device and shelves were returned to their pre-duplicate state with shelved items intact. I am able to add and delete items to the shelves normally and am able to create, edit, and delete shelves normally as well.

Hope this information is useful.

Edit: factory reset done March 2, 2013, didn't remove items from shelves before I did the above.