DIAGNOSIS Thermal shock. The BPA-free plastic blending jar is not rated for sudden, extreme temperature changes.
FIX There is no repair for a cracked jar. You must replace it. Use a metal pot or a heat-resistant glass container for blending hot liquids.
IF THAT DIDN'T WORK This is not a malfunction, it's a material limitation. The included jar is intended for cold blending, emulsifying, or storage, not as a cooking vessel.
HEADS UP Always let hot liquids cool significantly before transferring them to the plastic jar for blending. Or better yet, blend directly in the cooking pot, keeping the blade submerged to avoid splashing.