Large plastic components are prone to cracking during wave and reflow soldering. It is caused by moisture in the component expanding during the high temperature of the soldering operation. The cracking is either seen on the top of the device, which fairly obvious, as in the example, or on the base of the device, which is not so easy to detect.

Check the component specification of the part and the required storage conditions. Many of the QFP and TSOP devices require storage in special low humidity environments to prevent moisture absorption.