I've never seen those kinds of divots on the back of any wood. They almost look like vestiges of pin knots. Perhaps leaving some extra wood around the "pins" would have helped.
How long did you give it to rehydrate after heat treating? What was the nature of the correction? Did you check it with a moisture meter?
How far did you draw it before it popped?
I'm working on a BL bow that's 61 in tip to tip. I'll be lucky if I get a 25" draw out of it.
The wood just not have an affinity for long draws from short staves like osage does. In the past it has functioned well when at least 1.75 in wide and 64-66 in for a 26 in draw.
Look below on my post. PD gets mad when I say it s I won't.
Jawge