LDAP user on sub-sub Active Directory OU not found

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Steps to reproduce
1. Active Directory 2012R2 and accessed trough LDAP, owncloud users on "owncloud-group"
2. users on OU=ou-name,dc=domain,dc=it and added on "owncloud-group" ok
3. users on OU=ou-name,OU=ou-name,OU=ou-name,dc=domain,dc=it and added on "owncloud-group" are not listed and the test on LDAP form do not enumerate

Expected behaviour
all users added on owncloud-group must be a owncloud user.
(|(|(memberof=CN=owncloud-group,OU=ou-name,OU=ou-name,DC=domain,DC=it)(primaryGroupID=11657)))

Actual behaviour
only users on OU of point 2 are listed

Server configuration
Operating system: UBUNTU 16.04 - LAMP
Web server: Apache/2.4.18 (Ubuntu)
Database: Ver 14.14 Distrib 5.7.13
PHP version: 7.0.8
ownCloud version (see ownCloud admin page): 9.1.0.15
Updated from an older ownCloud or fresh install: fresh install using repository ubuntu
ownCloud log (data/owncloud.log, see https://central.owncloud.org/t/how-to-find-webserver-or-oc-logfile-enable-php-logfile/808): empty

Special configuration (external storage, external authentication, reverse proxy, server-side-encryption):
only external authentication

Integrity status for oC9+

Login as admin user into your ownCloud and access
http://example.com/index.php/settings/integrity/failed
paste the results here.
RESULT:
No errors have been found.