Not always. A limb can only bend so far before it starts pulling rather.
Next static bend you make. Try a 45 minute steam, not boil, and have your caul and clamps ready and right near your stove. Make the bend in one strong motion and clamp it. Its not proper I'm told, but its worked for me many times over. I've never had a crack like that, just a few slight tears that were all worked out in the end. Ive bent osage, yew, elm and hackberry all the same.