I had assumed something had been moved to the archive recently, but all of these were definitely old posts that had regained their "new".
The "Members' Mausoleum Archive" and most of the boards in it were just created yesterday afternoon, and whenever old posts are moved to any newly created board they regain their "new" status.
Why would clicking "mark as read" in the archive also mark all of the other categories?
Interesting - I've never realized that would happen. However, I've checked the SubBoards.php script and, trying not to get too technical, the reason it did is because the person who wrote that mod for SE tied the "mark as read" button that appears on any of the pages listing the boards for any of the subboards (i.e. boards like "Calendar Events / Announcements '02 I" in the "Members' Mausoleum Archive" and "Current Talk III" in the "General Discussions Archive") into the same routine that handles the forum's main boardindex's "mark as read" button (which marks
all the posts on
any and all boards as being read) rather than writing an entirely new routine that should only mark all the posts on the boards in a particular subboard.
I'll have to check to see if this is being handled correctly in the upcoming system. If not, I'll make a post about it on the developer's Web site so that it will hopefully be addressed while the new system is still in its beta testing phase.
Thanks for pointing this out.