Pe, that photo tells the whole story. I was not familiar with how these props were manufactured. I've not seen a cross section of the hub of one of these props. There is very little material around the hub and, obvious now, it's not solid to the outside surface of the hub. Crushing the hub has serious consequences. The smaller carbon props that I'm familiar with are solid throughout.

While I'm not into engine in this size range I might one day try. Seeing the inside of the prop has made it very apparent that the clamping force is critical. I hope that if I try a carbon prop the manufacturer supplies appropriate torque specs and also takes into account different bolt sizes and how this translates to clamping force.