Myself and one of my old NCO's both have civilian, no manual safety models of the M17. I am unaware of any real difference, other than coatings on the internals MAYBE, and while I've carried mine some with a loaded chamber and no issues, he has carried his for about 2 years now and it has not had any issues. The two incidents I know of have seemed to have involved holsters and depending on the holster, I would say it could definitely be the issue. The drop-safe issue, which has been corrected on newer models or through recall, was that it had to be hit with a very specific amount of force at a very specific angle on the back of the slide.
That's just what I know. I also know that when it comes to military and to a lesser extent LE, they don't always get the best stuff. SERPA's are not a good holster and I've replaced holsters for LE friends. We were issued SERPA's on my 2nd and 3rd deployments but they are less of an issue with firearms with manual safeties.