They all do that except for guns where the owner has bent the forward prong on the trigger bar inward to push the center instead of the edge of the striker blocker. That may affect the S&W warranty, don't know.

In my case I simply smoothed the outside of the trigger bar and put some grease between the bar and the frame. Solved the problem for me.

Keep in mind that there is a slight gap where the trigger bar pushes the sear and that can cause a sort of unusual feel at the beginning of trigger pull.