That M&P should be flawless out of the box, IMO. Did you give a cleaning before you shot it? I would say get a bunch of decent factory ammo and shoot a few hundred more rounds. If it doesn't happen again, I'd say you could probably blame it on the cheap ammo.

Could have been a combination of things. You are new to pistol shooting and you were using cheap ammo.

To compound the issue I was using some lower end 115gr rounds and since I am new to shooting handguns I may have been limp wristing a little bit.

While there is a brake in period for guns. The M&P should pretty much shoot right, strait out of the box.
Find a range officer and let him shoot your pistol. Using the same ammo you were using. Ask him to shoot a few mags worth and see how it goes. New shooters do at times have the limp wristing problem but that is not always the problem. Having to much flex in the arms can take away recoil enough to cause errors as well.
If all goes well with the range officer ask him or her to watch you shoot to see if they can catch you doing something wrong.
I know earlier this year a good friend of mine and I started going shooting. He knew I shot pistols and figured he was a pretty good shot himself.
After out first trip he asked me what he was doing wrong because he was all over the paper and I was holding a pattern, not a good one mind you cause it had been quite some time since I had been to the range but it was better than his. So I showed him where he needed work and now I am happy to say that on a good day he can out shoot me.
Which again is nothing to brag about but we are happy with his marked improvement.

Moral to the story is. As a new shooter, sometimes when we think we are doing things the right way. When we aren't, and sometimes need help. Just ask and there are plenty of people who will be happy to give pointers to get you shooting the way you want to be.

Thanks for the good responces. One thing I now notice is that we did not clean the handgun before using it the first time. The range was closing and they kept it open to let us put a few magazines through it so we didn't have time to clean it. Hopefully shooting it without cleaning first didn't damage the weapon?