Well, I just got a second pair of these for my wife and hers sound the same for me. The hiss is truly noticeable both in ANC and transparency modes. Bought directly for the Apple Store. I mean, it doesn't bother me THAT much to begin the hustle of replacing and probably experiencing the same issue again - so I'll just let it be. Do you still have the box of your pair to check what's the manufacturing date?
Yeah, I also feel that it's the way to go. Frankly, they do well with ANC in environments where you actually need it, like in the gym or during a walk. So hearing the hiss in quiet environments is a pretty fair tradeoff, I guess.