Hi everyone
A small update, now we must be sure FRS SYSVOL share are migrated to DFRS to allow a 2016 DC RS3 to be able to dcpromo.
https://support.microsoft.com/en-us/help/4025991/windows-server-2016-rs3-no-longer-supports-frs
Windows Server 2016 RS3 can no longer be added as an Active Directory domain controller (DC) to an existing domain that is still using File Replication Service (FRS) for replication of the SYSVOL share.