Scheduled Reminder edit form does not populate date criteria correctly when editing old reminders
When editing an old scheduled reminder as shown here (note, to be sent 30 days before membership end date):
the edit form populates incorrectly as shown:
This has caused our users to inadvertently render their reminder ineffective when editing unrelated items on the reminder (for example, the email text).
The log tables show what's happened here (extract from log_civicrm_action_schedule):
Apparently at some point, the coding for membership end date changed from "membership_end_date" to "end_date" but there was no accompanying database update performed to retrospectively change legacy reminders.
I should note that the reminders are actually still sent, but this bug with the edit form has caused grief for some users.