I have noticed the same problem this morning. I kept getting a reminder on the same task, about every minute or two. I deleted the task and removed it from the trash and it kept sending me notifications over and over until I turned off all notifications. There have been numerous problems with reminders over the past few weeks. I wish they'd get this fixed. Reminders is one of the reasons I signed up for pro membership.

For what it's worth, I'm suffering the same issue too. A reminder for 3pm local time today came around, which I've not ticked off yet, and I've been getting a push notification and an email for it about once every 4 minutes and it's not letting up.

On iOS the app badge is showing that there's 4 tasks left today when there's really only 2.

I can't see any simple way of fixing this, and it pretty much renders the app useless when the only possible fix is to remove it everywhere to stop the intrusion.

I had constant email reminders (every one or two minutes) for a task that fell due recently. I went into the RTM settings in the web interface and deleted all the notification settings.
The constant emails stopped.
I added back exactly the same notification settings as I previously deleted and everything is working normally again.
Looks like an intermittent problem with the RTM notification system as it has been ok since,

Hi everyone,
Sorry for the delay over the holidays and sorry for this issue!

If you're still experiencing this let me know and check into this this week. Our apologies!