Status:active / Status:undefined

I was doing some tag editing via the tag script and found I had somehow inadvertantly added a "Status:active" tag to a bunch of posts. So I went in to delete them and though I could remove them it added a "Status:undefined" tag in it's stead. Is there some meaning behind these tags or is this a bug?

I'm guessing by the syntax if it is supposed to be there it isn't supposed to show up in the tag list. I know I didn't intentionally add this tag, so some part of Danbooru or an extension must have.

Looking into it there also exists a "Status:pending" with one post in it (which is not pending approval BTW), and "Status:deleted" with two deleted posts in it. At first I was a bit worried something was really broken because non-mods shouldn't be able to set those statuses, but they appear to not be attached to their functions. I just wonder how they got there.

http://trac.donmai.us/ticket/271