Some threads not showing up unless searched

[Trace17]

I noticed this once about a month ago, but passed it off as an hiccup with the site and ignored it (it was a Curb Your enthusiasm thread in the tv section). But yesterday I posted in this thread:

https://forum.blu-ray.com/blu-ray-ga...oming-psn.html

in the PS3 section and now it doesn't show up in the PS3 forum list. I never saw a reply until I searched for the thread, and it showed up. This was the same with Curb a month ago. Then today I got bored and checked the site on a school computer and saw another thread (here: https://forum.blu-ray.com/blu-ray-ga...n-pandora.html) I had never seen before. I was logged out too. But when I got home the thread doesn't show up.

Anyone have any idea what the deal is? It's a very small number of threads I don't see listed. I logged out and checked again at home and I still can't see them unless I search for them.