I was curious if you were experiencing any failures for the slide to lock back on the last round. This can happen if you are having true limpwrist failures.
The thing with the 30S is it uses a lighter slide than the original G30. I don't know for a fact, but I suspect that is also uses a slightly heavier spring. When you combine light slide, heavy spring, and very light frame, you have all the key ingredients for a limp-wrist prone handgun. (This is one of the reasons why you can't make a gun with a super light slide and just make up for it with a stronger spring.) Grip it tight, no problem. Grip it weakly or in one hand, and you can run into short stroking issue where the slide doesn't make it all the way back. The next round may fail to feed for two reasons. 1. It doesn't have a "running start," so it may get hung up where it normally wouldn't. 2. The slide might start to strip the next round before it's fully in position. The round isn't pushed all the way up, so the rim doesn't ride up behind the extractor all the way. This puts the round at the wrong angle against the front of the mag, causing it to tip up high and miss the chamber. If you look at the back of the case next time you get this jam, you will find the rim isn't under the extractor at all, and the extreme angle of the round ensures there's no way that it is gonna happen, anymore, at that point.
Because the new spring made it worse, I think you might be having true limpwrist malfunctions. The stronger the recoil spring, the worse it gets.
The solution for this could be hotter ammo or a weaker spring (just keep shooting it).
The new extractor parts might have helped, too. If the extractor is too tight and/or sprung too strong, it can hinder the case from sliding up behind the hook. I have had a gun that needed just a little filing/polishing on the extractor hook to fix this kind of failure to feed. The nose of the bullet was actually making it into the chamber, hitting the top of the chamber. But the round wouldn't "straighten" and go in, because of the tight extractor, so it would just stop maybe a half inch out of battery.