I never heard that the X5 is different. I agree that the issue must be in the FCU. There is talk of "tolerance stacking" due to MIM parts made in India. If that's the case, there is a fix but it would require Sig to do it...they'd probably have to exchange the FCU if they ever acknowledged it.
At this point, I do not believe that these pistols just randomly discharge by themselves. But in any case, if they (or even some of them) are "touchy", that is a matter or concern. I have a couple, but they are not my EDC. I have several pistols of different sizes and types from which to choose depending on the situation. I am as facile with a 1911 as I am a DA/SA, striker, or revolver (ever see one of those things? lol).
Its interesting that the P365 and it's variants have not displayed this kind of behavior as far as we know. And despite the massive number of 320s that have been made and sold, there must be a million P365s out there by now. So there's that.
Then there's this: "And just this month, Sig Sauer announced that the Michigan State Police is adopting the M18 as its primary sidearm." I'm not saying this is any sort of vindication, but I'm thinking it will push the ball a little further down the road of understanding what's happening and maybe a solution.
"Somethings happening in here,
And you don't know what it is,
Do you, Mr. Jones"