We tried to upgrade our Samba AD DC server from 4.5.x to 4.6.x. After the upgrade, the tab of "Unix Attributes" in ADUC (Active Directory Users and Computers) disappeared, thus we could not use ADUC to manage users' "Unix Attributes" any more. When reverted to 4.5.x, the "Unix Attributes" tab showed up again.
Since there was no problem in 4.5.x, the configuration and data should be OK. It seems like an issue in the new 4.6.x.
idmap related configurations are as follows.
idmap_ldb:use rfc2307 = yes
#idmap config * : range = 50000 - 59999
idmap config RD : backend = ad
idmap config RD : schema_mode = rfc2307
idmap config RD : unix_nss_info = yes
idmap config RD : range = 10000 - 49999
winbind nss info = rfc2307