New Posts Since Last Visit

[CaptTom]

Using the web site, I like to click "New Posts" to see what's changed since I was last on. Usually, I just scan down until I reach the page with the bold line that says:
"The threads below have not been updated since your last visit but still contain unread posts."

However, more often than not lately, that line is at the very top of the first page. This is obviously not correct, and I have to page down until I'm at the time frame of when I thought my list visit may have been.

Any idea why this is happening?

I typically only use the same computer to access this site, and I never use the mobile app.

Thanks!