Last visit marker trigger?

Whenever I check back in, I’ll scan through all the latest messages since my last visit in all categories, to see if it’s anything I’m interested in, or anything I might be able to contribute to (i.e. questions about this or that).

While I’m the opposite of fond of sites that continually add content to a page, rather than doing proper pagination, there is at least one feature of the forum software which seems pretty useful - the red line with “last visit” in the middle. I suits my browsing pattern in particular. However, it’s very much not reliable.

So my question is, does anyone know what the trigger is to update the position of this line? It’s definitely not simply visiting the site. Nor is it opening a topic above the line. I very often see the line positioned below posts I’ve already seen (which have no replies at all, much less new replies), and often ones I’ve opened and read. I’d like to be able to do something to definitively update this line so I can save time on my next visit.

Thanks in advance for any helpful information.

Personally never paid attention to this feature.

I searched up on Discourse meta and found this thread. Looks like it’s not very reliable for other forum users too.

Sometimes it works, sometimes not. I find it more reliable to check the download date of my newest scripts (right click file, check properties) and start there on EroScripts.