Last post (some time ago) by (person who made FIRST post)

Title says it all. For example, as of the time I write this, I see "Web UI for Petit Modem, Last post 8 days ago by NeatNit", the first post is by NeatNit and the last post is by Lumage. I understand the wish to have the original poster's name associated with a thread, but that part of that sentence is the wrong place to put it: perhaps, "Web UI for Petit Modem, by NeatNit, last post 8 days ago by Lumage".

Ah yeah, I'm sorry about that. The original bug was that if two people posted at the exact same time, the "latest poster" would show up incorrectly for one of them. This was because I was grouping the database results by thread and then joining the max post date with the posts table on equal dates instead of equal post keys. I changed this to check post keys instead, however I forgot that you can't select other fields on a MAX grouping in MYSQL (a poor SQL design decision in terms of usability, but I'm sure it makes the speed better). This meant that, as you said, the first poster showed up as the last poster. That field should definitely be the last poster; I believe this is fixed now.