That is a bit of a mess up. Do you have a screen of the updated kills? I'd say it's a database issue, from the looks of the screen you posted.
Have a look at this post for a potential fix:
http://www.wowinterface.com/forums/s...055#post279055
This is from the live 5.1.6 version, so there could be a mixup. However, in the short term, it could solve your issue.