Here's my completely novice theory. It looks like there is a knot in the osage just to the handle side of the break. Knots cause a stiff spot. And, this knot is just at the taper of the handle fade where the bow should be bending slightly. So you handle= stiff area, then you have knot = stiff area, followed by a node= weak spot. The node area was absorbing on the preasure in transition from handle to limb. Like I said this is a novice theory. I've never attempted a lam bow.
Dave