[Samba] windows workstations needing reboot to validate passwords. --ADDENDUM

[Ray Klassen]

I am (earlier reported under the subject "Peculiar Problem") having an
issue that started several weeks ago, where windows (10 pro, server
2019) computers randomly get into a state where they refuse to validate
passwords. Rebooting (sometimes several times) makes the problem go
away. You can also log in if you disconnect the PC from the network and
then reconnect.

List of changes around the time it started.

Samba upgrade to 4.19.2
Samba schema upgrade to 2012_R2 functional level 
Samba upgrade to 2008 functional level

List of measures taken (hoping that if best practises are not being
observed, implementing them will fix things!!)

Moved DNS from SAMBA_INTERNAL to BIND_DLZ
Moved ntp from ntpsec to chrony

Diagnostic steps

Packet dumps (decoded with keytab) and loglevel 255 show no glaring
issues or errors.

Going to try restarting all of the DC's next time it happens to
determine if the miscommunication originates with windows or samba.

Windows Eventviewer lists failure as 
Event ID 4625
Status 0xC000006D
Sub Status 0x0
Failure reason %%2304


Any other suggestions welcome!!