That was indeed the main area of the failure. I think you're absolutely right about the design contributing to the break. Your bow, which definitely has some major ridges, is a way less stressed design- pretty long if I remember correctly, and bending through the handle.
I think the high stressed design of mine, plus the irregular distribution of tension are both responsible for the ruinous outcome. The reason I ultimately blame the ridges is that at 65" long bow with 1 1/2" of fade and only about 3-4" of non-working recurved tips should have plenty of working limb for a 27" draw. If it were a flat-backed piece of say hard maple, I think it definitely would have survived. Oh well, live and learn.