Has anyone else noticed a crack in the frame of the their CZ-52's? In the past month, I've replaced the frame on mine and it cracked again. Both times, it's happened in the thin section on metal on the top left side of the frame just behind the feed ramp. This is directly opposite the gap on the right side where the side plate stops behind the feed ramp. It's above the hole where the slide stop tab rides on the magazine follower. All I shoot is current production S&B. Since noticing the crack, I've put about 200 rounds through the gun and it hasn't gotten any worse. Is this a characteristic fatigue crack? I don't think this is a stressed area. Can I continue to use it without fear a bigger problems?