Hi, Haven't seen a master Airscrew prop throw a blade. How ever that isn't saying it doesn't happen as in your case. Some rules about using molded props though including all types. always flex the prop before you buy it and every now and then flex the prop before flight just to be sure it hasen't been damaged. Do this by holding it buy each end and flex in both directions. When on the motor hold the spinner and flex each blade in both directions. Also make sure that the edge of any spinner installed does not contact the prop at all. There should be about 1/16" clearance all the way around the blade. Props especially moulded props flex a lot between idle speed and full throttle. If the prop blade it touching the spinner it will cause a fracture point at the hub. It also doesn't hurt to boil molded props this will expose any flaws inside the prop like air bubbles, if there is a falw it will fracture and boiling will also reintroduce moisture into old props.