My configuration is
DC1: (first DC upgraded with calssicupgrade to AD with 4.1.13) now under 4.2.0rc2
DC2: joined and promoted as a DC with 4.1.13 now under 4.2.0rc2

DC1 and DC2 use BIND9_DLZ dns backend
DC2 works well

with no modification in smb.conf, winbindd cause samba to crash with this lines in log:
/usr/sbin/winbindd: winbindd version 4.2.0rc2-18.1-3327-SUSE-oS13.1-x86_64 started.
/usr/sbin/winbindd: Copyright Andrew Tridgell and the Samba Team 1992-2014
/usr/sbin/winbindd: debug_lookup_classname(winbindd): Unknown class
/usr/sbin/winbindd: Maximum core file size limits now 16777216(soft) -1(hard)
/usr/sbin/winbindd: Registered MSG_REQ_POOL_USAGE
/usr/sbin/winbindd: Registered MSG_REQ_DMALLOC_MARK and LOG_CHANGED
/usr/sbin/winbindd: lp_load_ex: refreshing parameters
/usr/sbin/winbindd: Initialising global parameters
/usr/sbin/winbindd: rlimit_max: increasing rlimit_max (1024) to minimum Windows limit (16384)
/usr/sbin/winbindd: Processing section "[global]"
/usr/sbin/winbindd: added interface enp2s0 ip=192.168.2.8 bcast=192.168.2.255 netmask=255.255.255.0
/usr/sbin/winbindd: added interface enp2s0 ip=192.168.2.8 bcast=192.168.2.255 netmask=255.255.255.0
/usr/sbin/winbindd: initialize_winbindd_cache: clearing cache and re-creating with version number 2
/usr/sbin/winbindd: Added domain BUILTIN (null) S-1-5-32
/usr/sbin/winbindd: Added domain XXXXXX XXXXXX.windows S-1-5-21-9999999999-9999999999-999999999
/usr/sbin/winbindd: Failed to fetch our own, local AD domain join password for winbindd's internal use
/usr/sbin/winbindd: unable to initialize domain list

This is my smb.conf
# Global parameters
[global]
        log level = 3 winbindd:255
        workgroup = XXXXXX 
        realm = XXXXXX.windows
        netbios name = DC1
        server role = active directory domain controller
        idmap_ldb:use rfc2307 = yes
        #server services = -dns +winbind -winbindd
        server services = -dns
        tls enabled = yes
        tls keyfile  = tls/DC1.key
        tls certfile = tls/DC2.pem
        tls cafile   = tls/CA.pem
        dsdb:schema update allowed = true
[netlogon]
        path = /var/lib/samba/sysvol/XXXXXX.windows/scripts
        read only = No

[sysvol]
        path = /var/lib/samba/sysvol
        read only = No

for having samba working I need to change the winbind in smb.conf:
server services = -dns +winbind -winbindd