I've seen that problem with other guns. The cause is usually pretty simple but the solution can be more complex.
It's been my experience that when the slide locks back with a round still in the mag that last round is in the mag a little cattywampus which allows the bullet to contact the slide stop and push it up.
Usually this has been the fault of a defective follower but if it is happening with all five mags then you need to look deeper for the solution.
I'm with the other guys, my first call would be to S&W.
Are you contacting the slide stop? I had not shot my Colt .45 in some time and I would keep having the same issue.. I found it was my grip. I was hitting the slid stop under recoil. I had not shot it in about 15 years.. LOL!! George