I have several gathered Sophias and they have all held up, except one. The Raspberry one. I had this bag once and gathers loosened. Then this bag got stolen from me. I replaced it with brand new one and I can see it starting to loosen again. Therefore I am convinced it is problem with the raspberry
My gathered graphite leather Lindsey had the look of almost loosening. I go to school in a humid climate. Brought her back to my hometown (which has a very dry climate) and she's held up fine since. I can see why CS warns against using leather moisturizers since that's essentially what the climate was doing to the leather.
I saw a woman today carrying a black gathered 1st generation Sophia, the same one I own. The gathers weren't coming undone but the bag looked terrible. It was droopy. It isn't humid here so that isn't why. I think it probably could get this way just from a lot of use.