When I look at my User Control Panel (UCP), I see a list of threads that have been updated. These are listed in bold. Threads that have been updated recently but that I've already read are listed in normal print.

Lately, when I've read the threads listed in my UCP, then reload my UCP, some threads will not "unbold" (meaning, shown as read) until I've read them again. To be utterly unambiguous about this, there have been no new posts added to the thread since the last time I read it, and I have read all the posts in the thread. To read the thread, I am clicking the down arrow to the left of the thread title, not the right arrow next to the poster's name. The time between reloads is in the minutes range, not the seconds range. If I then re-read the thread, and reload again, the thread goes from bold to normal.

This is new behavior in the last, say, week or so. My first thought is that one of the database servers is running out of sync with the other either due to load or hardware problems, but I'll leave the detective work to others. I hung up my root password years ago.