It sure looks to me like it's either a manufacturing defect (maybe they're both from the same batch?) or a failure related the inherent design of the blades...possibly combined with other factors that have already been discussed. As far as alternate brands go, I'll throw my two cents in for Graupner props. Grey reinforced resin, extremely rigid, yet durable. I've had many that have survived some pretty serious prop strikes, I think I've only actually had one or two break and that was under severe abuse. They're also the only props I've ever found that seem to perform as well as the old-timey Top Flite Super-M props. On various aircraft in my stable, they've proven themselves to perform as well or better than APC. Might want to give 'em a try, at any rate....good luck!