Real Time Visitor Count - Unlikely gap in visits and actions number


I would like to know more about how the real-time visitor count widget works.
I saw the ticket New dashboard widget to show real-time visitor count · Issue #3131 · matomo-org/matomo · GitHub which explains that the tracking pixel sends an update request every 10 seconds or so to tell the server that the user is still online.
But on my website, I can see any update request when I’m staying on a page more than 10 s while moving the mouse.
So, how the figures displayed on the widget are computed ?

I also noticed than sometimes, between each update (every 5s it seems), the figures can considerably change.
For example, here, I have 5 visits and 5 seconds after, I get 50 visits, and after 5s again, 15 visits.
It seems hard that 45 visitors connect the website in the same time, and 35 visitors quit it after.

I also have so much actions for the number of visits. For example, I get something like 800 actions for 15 visits, so 53 actions/visits in the last 3 minutes ::o

Can you help me to understand this behavior please ?

Thanks :slight_smile: