The corners on my sig carly did that. They faded and then they frayed. I returned her for a Julianne a few weeks before christmas.
I've only had mine for about a month, though I've been using her almost every day, and mine is not fading at all. I did spray mine before use, but that usually doesn't prevent wear, just prevents water damage. I don't see any sign of wear on mine at all, really.
I think that would be considered normal wear and tear. It has to do with the surfaces the leather is touching on a daily basis. Are you rubbing/bumping the corners on stuff as you walk by? Setting it down on rough surfaces?