Since your source is a YOUTUBE video and you have shown that your credentials and knowledge of SIG is without reproach, I choose to ignore this. He talks about a SIG with a Manual Safety, he talks about SIG that he admits did not go back for the repair, which makes him unreliable as a source. The manual Safety locks the entire action, while the upgrade has a firing pin block that can only be release when the trigger is fully pressed. I have not found 1 reputable major gunsmith on many of their websites mention this. Wilson even uses this weapon for his enhancements (but other that a gray guns type trigger, everything remans the same)
So until I hear something official; i.e. a recall, a major news break by several leading gun magazines that I trust, I will just continue to use my 320. Oh, by the way, keep your finger out of the trigger guard when you re-holster. There is no such thing as speed holstering.