Here's how this shakes out amongst our crew:
Kat, who carries the Daylight Briefcase against her hip, finds that the adjusted shoulder strap attachment points allow her to carry the bag even more comfortably.
Mike, who carries the Daylight Briefcase with the shoulder strap shortened quite a bit and the bag worn almost messenger-style against his lumbar area, experienced what @areohbe is describing -- he could feel the snaphook and snaphook attachment point against his back.
We had a conversation today over in customer service in which we shared w/everyone various shoulder strap attachment point options that we considered, tested, decided against, etc. In summary, the adjustment we made to the shoulder strap attachment points was the best option and perhaps an even-better-than-the-original option considering that, when Nik designed the Daylight Briefcase, he envisioned it being carried briefcase-style: on the side of the body, against the upper hip. That said, some folks (hey @MikeV) do carry the Daylight Briefcase more messenger-style. And to those folks we say: perhaps this will inspire us to design with a Daylight Messenger.
I realize that's not the best of news if you're happy with the design of the Daylight Briefcase and want to carry it more messenger-style. Sorry

Though the zipper issue was/is incredibly rare, it is nonetheless something that we wanted to proactively address.