I understand where you are coming from. It is hard to believe that this unit would have passed its ATE testing at our factory with this behavior, so either something has changed in the unit or it is being subjected to a condition that is causing unexpected behaviors. ADI has a failure analysis service that we can use if needed, but can you offer more details on the setup? Here is what I would be looking for:
1. Reset pin: What is this connected to? Any opportunity for noise?
2. Supply noise, drop outs, etc.
3. SPI signal integrity, timing, etc.
If you feel strongly that unit is misbehaving, you can request a failure analysis from ADI, through your point of sale. When doing this, make sure that you reference this discussion and provide as much detail as possible. The better information our F/A engineers have, the more likely they are to help you find useful insights in this process. I look forward to your feedback.