Sorry to hear about your P3P. I know how tough this must be for you as we spend a lot of coin on our birds. You also state how much you have a routine on flight checks, only to find out a prop is most likely the culprit rips your heart out of your chest as your pre flight check should of caught it!
The frustrating thing that we must all understand and take seriously is that although these are in much of a way toys. They are actually unmanned aircraft that defy the laws of physics and fly with some of the latest technology out in the open market. They are a tool with extreme precision and we must respect them and what they can do.
In all my years in the Fire Department and the Military on the flight line. Pilots double triple check their birds religiously before and after every flight for anything that can cause the bird to fall out of the sky. We must all make sure that we look over our birds with extreme scrutiny in hopes that we actually find a problem. At least by doing so will lower the percentage of birds falling out of the sky due to a mechanical failure!