Glock Leg has happened with other holsters too. But in the case of the Serpa, it happens with 1911s too (warning.....F-Bomb and SoB after he shoots himself):
https://youtu.be/zYvAxLX6OzE
He shows two holsters.... the Safariland "thumb drive" holster that he’d been using earlier in the day with a Glock, and the Serpa he was using with his 1911 when he shot himself.
He blames himself, not the holster. But I’d contend that some equipment creates the environment for higher risk than others. I like the Safariland thumb release system. You couldn’t pay me to use a Serpa, regardless of what gun I was using.