Suddenly started having a variation of this problem tonight. No new unread threads now, but I'll do some testing and analysis tomorrow when some threads with new unread posts threads pop up.
Using Chrome (latest) on WinXP SP3. Will see if I can duplicate in IE/FF/Safari and check on Safari and FF on Mac OS 10.5, too. (That's a lot to test...will see if I can get to that all!

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