I think I noticed this once in a while before, but starting... maybe Tuesday the 23rd? possibly Sunday? (according to a friend)... it seemed to happen much more often.

I noticed it was somewhat repeatable when you clicked on Profile - not every time, but every so often. It would not happen when navigating anywhere else on the profile or elsewhere in the site.

Others have experienced this as well, although I am unsure whether they're all using phones to access the site, although at least two others are.

I see that too! I'm on desktop. For example, this page says "Who's Online (0)" and then after I clicked Reply, it's says "Who's Online (42)". Now after a few moments of typing this reply, it says 0 again.

To get a little more tech detailed, I see in the Firefox console that cometchat_receieve.php comes back to the browser with buddylist: [], which explains the 0

Has to do with how those caches are emptied every minute so that What's Online can be sorta accurate without killing our DB's. It's taking a little longer to repopulate each time, leaving a gap for a few seconds with 0 users, so I'll look into that

Often happening on both my imac & ipad too