I know I'm late here, but the only times I had cracks that looked like that were when I got too aggressive trying to take twists or lateral wobbles out of staves and left them too thick. So, torsion. I mentioned because I see a raised knot in the pic just left of the crack, and near the clamp.
I had this really cool BL stave like that once with side to side wobbles, like banked hairpin curves on a motorcycle track. Well one went right through the handle, so the faces of the limbs right off the fades were about 10-15 degrees off of parallel. I cranked them around a lot on a form and tried to cook them in place with the heatgun, but immediately a crack like that opened on the top fade on one side, and the bottom fade on the other. Ruined it.