View First Unread intermittently not working

[Whistler]

A new quirk over the last week or so is that in the forums, the "View First Unread" sometimes does not appear when I in fact have unread comments in that thread. Most of the time it does work, but is now not working enough of the time to be irritating. Any insight into why?

[RAY@HQ]

Had not noticed this, but will start to look for it. We have not done any recent upgrades or anything like that.