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.

Hi...I'm one of those Mentioned by Tsarmina.
I'm finding that the online people keeps telling me there is 0 people online.
I'm also finding if I move from page to page, eg forums to profile, my convo gets deleted.
I'm also on my mobile.

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