If your SW is running code with logic, then it can change based on the decisions it makes; Like what data is programmed into flash, what pin settings are set, etc.
The MAC is obviously different, so that could be one possibility.
Could be loose/damage HW connections/components on one, but not the other.
Hi Florent Vidal,
Could you please let us know the failure rate? Are you seeing the failure in multiple modules?
Could you please check whether there is any soldering issues in the failed ones?
Hello, Thank you for your reply. In fact I had a soft problem that I corrected.