Have been experiencing the 12 round magazine being hung and the slide not locking open and the mag wont drop free. The mag follower should be under the slide lock pushing up on the slide lock as when the mag is empty. My 12 round mags tend to have enough play in the frame to allow the tip of the slide lock to end up beside the mag follower and not on top of it. Jams the mag and the slide does not lock open. Anyone else see this with their FNS9C?