Hi,
I think I know what's going on.
As I said, the plugin is made to send requests to the website only after you scroll down the page (or click on it).
And if I access the page and scroll down, after that, I can see the "check" requests sent to the server, so this is working:
i.imgur.com/c892MRj.png
However, after exactly 30 seconds, the page refreshes itself automatically. Because of this, it stops sending the check requests to the server and thus you would only be notified next time you open a page and do something on it.
So the problem comes from that system refreshing the page every 30 seconds.
It you get an order between the moment you scrolled and the 30 seconds, it works, but once the page reloads, it's finished.
Now I don't see why you have that in place.
This is usually done to make sure the user session doesn't time out. However, by default, the user session is configured at 15 minutes in the joomla configuration page, which is already not a lot. But that means that there should be no need to refresh the pages more than once every 15 minutes, unless you're using this mechanism for something else ?
But even so, it should be annoying for your users to get their form inputs cleared if they leave the page for a few minutes and then come back. something like 2 hours should be fine. And in that case, do you even need a keep alive plugin ? And if you do, you should have it refresh the pages only once every 2 hours.