I got this to work (10.4.3 server and 10.4.3 client), both with an encrypted bind and an unencrypted bind.
1: Built OD Master with a fixed IP address, FQDN that resolves in DNS, and with a valid SSL certificate
2: Bound a 10.14 client to the server using Directory Utility and checking the box "Encrypt using SSL"
3: Created an account, daffyduck, with a password daffy on the server
4: Set login window to user name and password and entered initial user name and password
5: Was prompted to change password
6: Set password to 123456 and committed the change
7: Change accepted and user allowed to login for first time.
When I initially tried this, I was on user name at the login window and I needed to click the account, then dismiss the change password dialog since I did not pre-auth with the original password. This allowed me to enter the original password which then presented the change password dialog. I was able to change the password but the change password box would not disappear. Pressing cancel, I was then able to login with the new password. (I cheated on this first test and used createmobileaccount command to prestage the account.