You may have more than one type of access for the same calendar on your dashboard. For example, you might have account-based access for a calendar as well as a shared calendar link. Or you might have multiple calendar links for the same calendar, and you've added all the links to your dashboard.
If you're the calendar admin, it can be a bit confusing to sort through all the links and open your admin-level access when you need the calendar settings.
Here's how to differentiate.
See more on decoding your dashboard here.