While I understand that for some platforms, like the 1911, the Serpa release puts your finger inside the trigger guard-that’s bad. For the Glock, M&P, and the Beretta 92, it indexes your finger alongside the frame. So I don’t see the issue there.
Correct me if I’m wrong, but the Marine Corps is currently the largest user of the Serpa. I still haven’t heard of any NDs yet from there. If someone is aware of them, I’d like to know.