Depending on your "method", this may not be an issue...I notice with my 9c that the slide stop is very tight/difficult to activate when the slide is locked OPEN. Many others have experienced this as well and some have even reported damaging their slide stop while trying to actuate. I almost always use the "slingshot" method to get the weapon to battery- when shooting my 9c, I always do- as that is the way I was taught and continue to be taught. I mention this only because it seems to be an issue with many 9c's. In contrast, my full-size MP9 does not have this issue (at least not as noticeable)...not sure why. Check out the M&P Sub-forum- lots of good info.
Hope you like yours after shooting it. I love mine- it has become my favorite compact shooter. I had some FTE (extract) issues early on. Sent it back and had the barrel replaced. Zero problems since. SW's customer service is fantastic.
Enjoy!