The phase of route I and route Q is often inconsistent after initialization

hi all：
When I want to do an IQ calibration, I found that the IQ output phase of the DAC was inconsistent after each initialization. The correct scenario is an IQ phase difference of about 90 degrees after initialization. But sometimes the phase difference is 60 degrees or less. This will result in a failure to calibrate.
I tried a few methods and used some registers to check for errors but nothing worked.

The following is the case where the IQ output phase difference is correct.

The following is the wrong situation.

So my question is what causes this, how can I fix it or what register can monitor it?

Best Regards