To me it seems like a fatigue fracture. I suppose it could have happened with OEM as well, it's just that I haven't heard of any such failures with OEM. Considering that airplane props and helicopter blades are often "color tipped" you would think DJI would do it if they could. Personally I stick with OEM for one reason only, if I have a blade failure with a NON OEM prop, DJI can use that as an excuse to avoid liability.