Had the same issue with my SF. Two fixes. You can grind a little meat off the U shape of the mag release, close to the end where the nub is that catches the mag. This will allow the mag catch to protrude deeper into the opening, giving it more area to catch the mag. Before I did this, I pried a little bit of the top of the metal on the hole where the mag catch goes.
One gets the metal closer to the mag catch, the other bring the mag catch closer to mag.