My guess as to what you are referring are the three different Popes named Benedict IX, and the fact that they link to the same article. But in reading about Benedict IX, it appears that he was in power three different times. Then, messing around with the web address I came up with these links:
Benedict IX (antipope) –
newadvent.org/cathen/02429b.htm
Benedict XI –
newadvent.org/cathen/02429c.htm
I know that this was one of the darkest times of the papacy, lots of antipope-ing going on, so I went to my *mostly *trusted source, wikipedia. It explains more clearly that Pope Benedict IX apparently held the office three different times, and discusses the reasons for that. My guess is that the somewhat confusing list, which doesn’t explain the details, however, is just a New Advent oversight. I find that the wikipedia articles can clear things up that the old Catholic encyclopedia can’t, as well as point out other problems. Honestly, given that all of this was happening less than a decade before 1054, I can’t fault the eastern churches for wanting to distance themselves from their Roman counterparts. Of course Patriarch Michael I Cerularius had his own scandals and political conflicts. Thanks though, that was a fun little detective game. Was this what you were looking for?
Maybe you were referring to the fact that the last eight popes have no articles. I think this simply has to do with copyright issues, and only the old encyclopedia, published during the reign of Pius X, is available online. If you read the article on Pius X, it speaks on current events and there is no discription of Pius’ death. Was this what you were looking for?
Pax vobiscum