I have an osage bow built by someone that rigorously followed the Massey formula and it has those same exact drying cracks up the belly. When it was originally made, the back barely had any crown and once it had cured out 6 months it had a fairly radically cupped back and expansive cracks.
The guy that gave it to me had met Jay at a South Dakota bowhunter's convention and showed it to him. Jay looked it over and pronounced it well made. The bowyer had other bows that he shot more and it sat in his closet for years before he gave it to me. For the first few years I had it, the danged thing would randomly make the most spine shaking, knee-jello inducing cracks from time to time and I was so sure it was gonna blow. I've left it out in the rain overnight on accident, left it for weeks in a vehicle in below zero temps with all but no relative humidity, likewise in the vehicle in 100 degree weather where temps inside the solar oven of the vehicle reached temps over 150 degrees, I've TWICE been so careless as to slam it in vehicle doors....and if I had to be abandoned in the wilderness, I'd take that bow over any other I have held, seen, or read about.
But the local SCA won't let me carry it within 50 feet of the shooting line because it's "unsafe". Yeah, for the deer it's killed!!!