Sounds like a freak accident to me. SEVERAL of them?
Sounds more like misuse of the hammock. It is rated for 250, so someone(or multiple someones) near that limit bouncing around or jumping in the hammock will most certainly split it. This thing is not a tank, it is UL for a reason. Doesn't have the 400lb rating like a doublenest. My lovely lady and I combine for ~245, give or take a lb or two and we have never had any problem laying in it together for naps.