In case you can't watch the video, this guy was able to reproduce an accidental discharge several times by putting a tiny amount of input on the trigger and wiggling the slide. He used a screw wedged into the trigger to consistently put the trigger up to the wall so it's hard to argue human error anymore. His findings seem to indicate that if you have input on the trigger, even if it's not enough to fire, and the slide is bumped, the gun can fire (at least for his particular gun).
Hard to say how common this will wind up being since there are tens of millions of P320/M17/M18s out there. Still...more bad news for Sig, and even a one in a million chance is enough for most folks to not risk it. I have one and, while I already never considered carrying it thanks to the lack of an external safety, I'd never even risk holstering it for matches or practice now.
The evidence really seems to be pointing to a low tolerance for out-of-spec parts in the P320 design. Any gun manufacturer is going to be incentivized to cut costs over time, so that's a really bad combo.
I don't have a Sig, but I was just out with somebody that does. Passing this along to them.