“But some of these claims are that it fired while holstered, which is a very different thing.”
And...people lie! All the time. Particularly when embarrassed or in search of money. And when it is both?
People do lie, but these reports have been coming in for years, since the first day that the P320 was on the market.
And the P320 did have drop problems.
And IIRC the P320 was Sig Sauer’s first try at a striker-fired pistol.