I've had my Sport (with black band) for 12 days now and I'm seeing the same issues. On the inside of the strap I see the same happening next to where the pin sits and then also right at the end where it obviously rubs on the other end of the strap. I don't mind this as I don't think it'll get worse and it's on the inside. What is bothering me a little, though, is that it looks like it might be starting to peel on the outside of the band, right where the strap kind of turns outwards where it meets the watch. It's not that noticeable but seeing as I'm in my 14 days I was wondering what to do. I think I'm probably going to leave it as it looks like even if they replaced it I'd be in the same situation in another 10 days.