Thanks for the input guys.
I detail stripped the gun and made sure everything was nice and clean (including the fp channel). I have a sa micro compact and have never had my grip bump the slide lock, but since the emp is a bit thinner maybe I was doing it and not realizing. Ill keep an eye on that when I go back to the range. I'm going to also see if it happens with one mag specifically, but hopefully it's just operator error!