yeah it seems to be that, if you @ someone that link comes back 404, but if you get them proper (from a comment or post) the page comes up. Thanks for pointing this out.
damn it chica you are all over this site (I liked a lot of the alt looks you posted and noticed it was all you), but your name if I open a new tab on it is golden, but all of theirs come back with the 404, but like @RheingoldRiver said it might be a bug related thing.