Okay, this is a wierd bug.
If you visit the page for April 3^rd [1] you'll see three entries (the final one added today [2] in trying to track down this bug). Now, if you go to the first entry of that day [3], then click “Next” you'll actually skip over the second entry [4] (which doesn't show up at all) to the third entry [5]. And from there, clicking “Previous” will either take you to the first entry for that day (which is what happens on my test server) or it take you back to the third entry (which is what is happening on the live server). On the plus side, it's happening on both systems. On the minus side, it's exibiting different behavior.
I don't know what it is about that second entry (which is about the House Chillin' Party [6]) that mod_blog [7] doesn't like …
[6] http://www.livejournal.com/users/springdew/272146.html