[Samba] samba-tool domain classicupgrade doesn't import givenname, sn

[banda bassotti]

environment: CentOS 7.x with samba-4.11.9 from
http://samba.tranquil.it/centos7/stable

local slapd with users entry like:

dn: uid=user1,ou=People,dc=dom,dc=xx,dc=lab
objectClass: top
objectClass: inetOrgPerson
objectClass: sambaSamAccount
objectClass: posixAccount
objectClass: shadowAccount
uid: user1
o: yy
mail: user1 at dom.xx.lab
gecos: xx xx
displayName: xx xx
loginShell: /sbin/nologin
homeDirectory: /home/xx
uidNumber: 1332
sambaSID: S-1-5-21-2201364573-426607711-3969381345-1664
sambaPrimaryGroupSID: S-1-5-21-2201364573-426607711-3969381345-513
sambaLogonTime: 0
sambaLogoffTime: 2147483647
sambaKickoffTime: 2147483647
gidNumber: 513
sambaHomeDrive: S:
sambaAcctFlags: [U          ]
sambaPasswordHistory: xxx
telephoneNumber: 111111
company: xxx
sambaPwdMustChange: 1338104547
ou: xx
sn: SURNAME
givenName: GIVENNAME
cn: SURNAME GIVENNAME
userPassword:: xx
sambaLMPassword: yy
sambaNTPassword: xx
sambaPwdLastSet: 1234567890

after classicupgrade: samba-tool domain classicupgrade
--dbdir=/root/samba3/ --realm=dom.xx.lab --dns-backend=SAMBA_INTERNAL
/root/samba3/smb.conf

all entries from samba look like:

dn: CN=user1,CN=Users,DC=dom,DC=xx,DC=lab
cn: user1
instanceType: 4
whenCreated: 20201125150054.0Z
whenChanged: 20201125150054.0Z
uSNCreated: 5053
name: user1
objectGUID: 6b9021fc-b8aa-4e17-8002-54aadf21b338
badPwdCount: 0
codePage: 0
countryCode: 0
badPasswordTime: 0
lastLogon: 0
primaryGroupID: 513
objectSid: S-1-5-21-...
logonCount: 0
sAMAccountName: user1
sAMAccountType: 805306368
objectCategory: <GUID=....
pwdLastSet: 132499826270000000
dBCSPwd:: DAAAAD...
unicodePwd:: DAAAA...
displayName: SURNAME GIVENNAME
homeDrive: S:
accountExpires: 137919572470000000
lastLogoff: 137919572470000000
logonHours:: ////////////////////////////
userAccountControl: 512
uidNumber: 1332
objectClass: top
objectClass: posixAccount
objectClass: person
objectClass: organizationalPerson
objectClass: user
unixHomeDirectory: /home/user1
loginShell: /sbin/nologin
gidNumber: 513
msSFU30NisDomain: DOM
uSNChanged: 5057
replPropertyMetaData
distinguishedName: CN=user1,CN=Users,DC=dom,DC=xx,DC=lab

without Givenname and Surname

I am not attaching the upgrade output because there is nothing relevant.
where am i wrong?

thnx