Q. ADPD4100/ADPD4101 power sequence problem?

I have a question regarding the ADPD4100/ADPD4101.

The customer made 6 boards of its own and all used ADPD4101.
Three ADPD4101s operate normally, but the other three do not.
(Sometimes it works normally.)

When ADPD4101 does not operate normally, the register is read as 0.

When ADPD4101 does not operate normally, turn off the power and turn it on immediately, and ADPD4101 operates normally.
However, if the power is turned off and turned on after 30 seconds, it does not operate normally.

The initialization sequence described in the errata documentation has already been applied.

Is there any problem with the power sequence or timing?
Please check quickly.