We are using ADAU7002 with INMP621 microphones. Occasionally we have found an unusual DC offset introduced. We've also found that the condition can be forced to happen by interrupting the clock signal briefly.
The data is serialised with a number of other microphones using an Altera device. I do not know enough about that process to know if that could introduce the problem - that is a possibility that we are discussing.
Are there any know issues that could cause this? We have noticed a DC offset is normal (around 3%) but when this situation occurs there can be many different offsets (thinking about that, perhaps that suggests the serialiser?).