I noticed the same thing on my classic flap when I’d had it only a couple of weeks and I never close the press stud closure ever. There is a circular indentation above the turn lock. I think it’s from the back of the press stud pressing on the leather when the turnlock is closed. I thought the impression would wear away after a bit and I always store it with the felt in place when not in use so it must have happened when I was out and about with the bag. It’s not got any better unfortunately. I’ve never had this with any other classic flap I’ve owned. I feel the caviar leather on my bag is super soft as I posted about another issue with the inner front pocket being very bendy and flimsy and causing some wrinkles and softness to the quilts towards the bottom of the bag.