I just started a new site and all the posts and categories were fine.
Now each one shows with CATEGORY ARCHIVE: in front of it.
The only thing I did differently was I installed TinyMCE and it did not work for my template, then I uninstalled it. At least that is when I noticed it. From then on all my posts have the CATEGORY ARCHIVE prefix.
I know I can delete it from the code, but I am wondering what I have done to trigger this problem?