Additional Reminders List and Calendars

[Gizmo22]

Currently use iCloud/Apple/Me address across a Macbook Pro on 10.8.x, iPhone 5 (iOS 6), and iPad 3 (iOS 6).

For some unknown reason, I repeatedly have a new Reminders list titled "Reminders" and Calendar titled "Calendar" popping up on any combination of the three bits of hardware. Deleting it from any bit of hardware just causes it to return a few moments later.

Deleting it from any two item combination, or all three, at the same time gives the same result. The Calendar and Reminder list are blank, and it is certainly a first world problem; not dire, but annoying none the less.

From the "more info" settings of the various devices, it says the calendar and reminder list are tied to my iCloud account. I have used the browser based iCloud site to delete the calendar and list as well, only to have it return immediately. I do have three other reminder lists, and one other calendar, associated with this iCloud account.

Any idea about what could be causing this?

Mac accounts:
Just iCloud set up for mail, calendar, reminders, etc.

iPhone and iPad:
iCloud and work Exchange server, Exchange server only set for contacts, calendar, and mail, not reminders