I've had this issue through multiple versions and multiple themes. It has happened on the left and the right sidebar, so it has to be a simple setting somewhere, right?
If I have no widget active in the sidebar, it doesn't go away. Instead, it displays widgets that aren't active. For example, right now my right sidebar is showing Recent Posts, Blogroll (from my Links list) and Meta. But none of these are active, and they don't show on my Widgets page. If I activate a widget in the right sidebar, the other items go away.
I have 2 active widgets on the left sidebar. If I deactivate or move them, three others show up. Categories, Posts by month, and then some sample widget text.
The site, if it helps, is LeanHRBlog.com.
Appreciate any help I could get. I'm trying to avoid poking around in the code, so I'm hoping it's an easy fix.