The slide being released upon vigorous insertion of the magazine is something that can happen with a number of the plastic pistols that use low profile slide stop lever engagement tabs. It's usually more shooter-related than specific gun related.
Slide release on vigorous magazine seating, is common place and like Fastbolt says, it's usually a shooter manipulation issue and not a gun issue. I'm a retired LE instructor as well (40 years worth) and worked for S&W and have seen this with all pistols. I have generally found that a shooter that is experiencing this is seating the mag and with a slight forward motion. This forward motion "unloads" the slide stop by causing the slide to momentarily and slightly move to the rear. The Slide stop is spring loaded to the down position, and now, with a loaded mag now in place, there is no mag follower to hold it in the slide locked position. Seat the mag straight in and just firmly enough to insure it's seated. Problem will disappear.