3585576 - Error "Number range XX is internal, do not enter a personnel number" in app Migrate Your Data

In Migration Cockpit, when simulating data by object "HCM - Employee" (SIF_HCM_EMPLOYEE), the following error occurs when the personnel number is filled in the template:

"Number range XX is internal, do not enter a personnel number"

However, if "Personnel Number" is not entered, an error message will appear during file validation: 

"Sheet YYY, field Personnel Number, row Z is empty; enter value for the mandatory field"

SAP S/4HANA

LTMC, MYD, CSV, files, tried, objects, project, prepare, simulate, migration, before, uploaded, missing, master data, employees, user, number range, numbering , KBA , CA-GTF-MIG , SAP S/4HANA Data Migration Cockpit Content , PA-PA-XX-MIG , Migration Cockpit , Problem