I everyone, I've got a feeling this one might need an S.R. but it's worth a go here first.
We’re having an issue where DSfW joined PCs (Windows 7 & 10) PCs will log out of all Office applications and Google Chrome (Including all logged in websites) after a user is prompted to change their password with a "Password has expired". Strangely this does not occur when a user initiates a password change themselves from CTRL ALT DELETE. when they are logged on.
We did some research, mainly the Chrome support forums, which suggested this was a Samba issue. They suggested the fix detailed here which solved the issue of us being logged out after every reboot: http://www.techsphere.org/linux-adds-and-winstore-problems/ but it still occurs after an expired password change.
A couple more posts suggest that this was fixed in Samba v 4.2:
As DSfW was still on Samba 3 we have been living with the issue and hoping that an updated version would fix the problem. However, we have since installed OES 2018 SP1 which includes Samba 4.6 but the issue remains.
This behaviour does not happen with local users or users that are connected to Microsoft Active Directory DS.