ADAU1761 SPI communication failure.

HI, I come across a problem with the use of ADAU1761. when there is a power-on, there is a certain chance that the configuration of the ADAU1761 chip fails.The DSP configures 1761 through SPI interface.In the process of product development, there are also cases that the configuration is failure. To solve this problem, we adopt the method of verification and rewriting. But recently we found that the DSP program has always been in the state of verification and rewriting,so the DSP system can not boot normally. The abnormal rate is about 2%.At this time, the software restart of the DSP still cannot solve this fault, and only the power-off restart can be successful. The SPI communication clock is set to 1Mhz. When the fault occurs , we found through debugging that the SPI interface of the chip could not respond to communication at all. My question is: Under what circumstances will this failure occur? Please reply so that we can locate the problem, thank you.