Membership 2 Pro Automated Emails Sending Too Often

I've got automated emails set to remind members about their membership expiring 5 days before expiration date. Three of my members each received 4 reminders about this in two days. Another user (one of my admins, and the site's owner) received twelve (12!) emails over the course of 3 days stating that his membership had expired.
That's not expected behaviour: They should received ONE reminder, five days before expiration and ONE notice that membership has expired. Please investigate. It's possible that two of the users received so many emails because the expiration date was changed once: It was delayed by two days. This might explain one extra email but not four. It also doesn't explain why the other three users also received four emails. Please advise.

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