Thanks for the update, Roger.
Yes, that could have a bearing. Something in your system reset that setting, for some reason. The best guess so far is that some 3rd party plugins wipe out that cron job, but I can’t say for sure. I still haven’t been told or found a way to reproduce the behavior consistently to troubleshoot it.
You can create a test user and give it an EOT time in the future that will let you get a reminder soon, and see if they’re being sent again now. And for users that missed past reminders, you could create a new one that would go out tomorrow, for example.
Adding a mail logger could help you monitor this while troubleshooting, too. https://s2member.com/kb-article/troubleshooting-email-delivery-problems/