I have just at 40 hrs on my frame, never crashed or a hard landing so I'm a bit perplexed by what happened today. Went out on a 20 minute flight, all systems normal and return once battery is low. Swap battery and then as I apply power for take off I notice a bad wobble in my left rear prop, try again and this time I see the crack. I struck nothing on my flight and so I'm curious if this is possibly a known issue with the P4 frames? Anyone else experienced this? Guessing the entire frame will have to be replaced, curious if anyone knows what those cost? Very fortunate I made it home as I was over water a majority of my flight. Appreciate any help or advice.