No, you do not have a problem.
I just inspected the RSAs on all my M&P guns. A couple look like yours and I haven't had any issues with them in a few thousand rounds.
When in the gun, the spring is held in place by the slide. That nut on the front of the guide rod isn't even touching the spring when the gun is fully assembled. It will only press on that nut when removed from the gun. Even if it were to slip past the nut, that would only happen when out of the gun so, the gun will continue to work.
If it did actually slip past the nut, S&W will replace it for free.
Well said, and this is my actual experience. After my spring slipped past the nut on the front of the guide rod, seemingly trying to leave the area altogether, I was able to get it back into the slide (through clever redneck engineering), and after doing so, the gun functioned flawlessly for another hundred rounds or so until it was replaced. I have every confidence the gun would have continued to function without a problem, since (like Rastoff mentioned) the spring is essentially "captured" by the slide in a way somewhat similar to other, non-captured designs.