The fact that nobody’s been able to replicate this without pulling the trigger is concerning.

That's what SIG is claiming. Yet lower in the article:

A video released in August that year by a Texas gun store showed the gun firing consistently when dropped at certain angles. The impact caused the trigger to depress, the video showed.

Assuming negligence on an individual cases makes sense. Happens. When you've got a cluster of reports centered around one specific model and there is evidence of said model firing without trigger being pressed...that's a lot of smoke to be insisting there can't be a fire