Now the updates are removing the custom email password change (CMD_CHANGE_EMAIL_PASSWORD) template folder:
/usr/local/directadmin/data/templates/email_pass_change/custom/index.html
This may have been happening since previous updates, not necessarily 1.668, but we only identified the problem now. Unfortunately, new updates often bring new unpleasant surprises or bugs. It would be important for you to perform better quality control of updates.