There are times when Watched Forums shows forums with new posts. I go to a forum, go through the new posts, and click the back button. And the remaining forums no longer correctly display the 'new posts' indicator. Sometimes going forward and back again corrects the display; sometime I have to go back to the home page and click Watched Forums again. Similar things happen when visiting a forum with unread posts. I go to a thread with new posts, read them, click Back, and other threads that had new posts no longer have the indicator. Just now, looking at the 2nd Gen forum, the thread I just read vanished from the list when I clicked Back. But the forum display was OK when I went back again and re-entered the forum.
I occasionally--rarely--see DB errors. For example, I might click "Mark All Forums Read" and it usually does just that. But sometimes it grouses that it can't. Go back and try again and it's OK.
But it happens inconsistently and irregularly. There are days, even stretches of day, when the system seems flawless.
I only have 2nd Gen, Other Veh, Other and Politics forums in the watched list.
It's been happening 2-3 months now, or longer. I would *almost* suspect something flaky in DB read/fetch operations, especially if it's related to system load; I haven't seen any evidence of data corruption, only oddities seemingly related to fetching and displaying data.