[Samba] GPO fail and sysvol perm errors

[Sonic]

GPO's fail to apply on Windows clients and sysvol permission errors are logged.
DC is Samba 4.13.0 created via a classic upgrade.

Logged sysvol errors (uid 5025 is the system I ran gpupdate on, don't
know what uid 3000011 refers to):
===================================
Oct 25 12:17:09 srvr01 smbd[3762]: [2020/10/25 12:17:09.695062,  0]
../../source3/smbd/service.c:169(chdir_current_service)
Oct 25 12:17:09 srvr01 smbd[3762]:   chdir_current_service:
vfs_ChDir(/usr/local/samba/var/locks/sysvol) failed: Permission denied. Current
token: uid=3000011
Oct 25 12:17:41 srvr01 smbd[3762]: [2020/10/25 12:17:41.927671,  0]
../../source3/smbd/service.c:169(chdir_current_service)
Oct 25 12:17:41 srvr01 smbd[3762]:   chdir_current_service:
vfs_ChDir(/usr/local/samba/var/locks/sysvol) failed: Permission denied. Current
token: uid=3000011
Oct 25 12:19:40 srvr01 smbd[3780]: [2020/10/25 12:19:40.865699,  0]
../../source3/smbd/service.c:169(chdir_current_service)
Oct 25 12:19:40 srvr01 smbd[3780]:   chdir_current_service:
vfs_ChDir(/usr/local/samba/var/locks/sysvol) failed: Permission denied. Current
token: uid=5035, g
Oct 25 12:19:51 srvr01 smbd[3780]: [2020/10/25 12:19:51.767427,  0]
../../source3/smbd/service.c:169(chdir_current_service)
Oct 25 12:19:51 srvr01 smbd[3780]:   chdir_current_service:
vfs_ChDir(/usr/local/samba/var/locks/sysvol) failed: Permission denied. Current
token: uid=5035, g
Oct 25 12:31:01 srvr01 smbd[3842]: [2020/10/25 12:31:01.462208,  0]
../../source3/rpc_server/rpc_server.c:1086(dcesrv_auth_gensec_prepare)
Oct 25 12:31:01 srvr01 smbd[3842]:   dcesrv_auth_gensec_prepare: Failed to
prepare gensec: NT_STATUS_INVALID_SERVER_STATE
===================================
Windows system log provides:
===================================
The processing of Group Policy failed. Windows could not apply the
registry-based policy settings for the Group Policy object
LDAP://CN=Machine,cn={E2BC0255-64C8-42CF-A27A-59A7D3DCD2DC},cn=policies,cn=
system,DC=my,DC=example,DC=com. Group Policy settings will not be resolved
until this event is resolved. View the event details for more information on the
file name and path that caused the failure.
===================================

How to solve?

Thanks,
Chris