Hello Laurent,
have the changes to the other fields (passwords etc) the same timestamp from your stand-alone job or are they updated by IdM later on? Could it be, that you have a scheduled job, that reads changes from SAP back into IdM (like every 10 minutes or something like that) that could trigger a normal modify-ABAP task for these users?
Is this happening for all users, that are found by your job or just some?
And I think Pradeep meant, if you have checked in your job log, if other jobs were running at the same/similar time, that could also be the reason for the updates.
Regards,
Steffi.