I find that the scratches on my Legacy bags (the scratched surfaces always appear much lighter) disappear and the deeper colour is fully restored and consistent. Maybe this whitening is just like a scratch. I hope my suggestion helps.
If the edging on my leather bag wears off like that, I'd grab my Apple and try to do some damage control ASAP.
BTW, get the Apple Leather conditioner and not the Coach version because the latter contains silicone and it coats and chokes the pores until the leather drys and cracks over time.
Get Apple instead because it doesn't contain silicone.
If you ask the Coach SAs about that, they'd deny it and try to promote their product over Apple. It's this forum that will keep you on the straight and narrow. Coach doesn't always tells the truth--they're focussed more on the bottom line and they'd tell you to get the Coach leather conditioner too.
Thanks for the tip!! Now where can I get some of this wonderful Apple product???