Button Clock Out dessapear

Good evening,
I have this plugin installed on my web site, and I have the problem.

So here’s the thing: when I click the “clock in” button to start counting my user’s time, the time starts counting normally. the problem arises when I spend 8h (for example) with the elapsing time, and then when I return to the Time Clock page, the “Clock out” button is not available! that is, when I want to stop time the button that is shown to me is the “Clock In” button again. But time continues to count …

What could be happening ?!

Note: sometimes when I refresh the page, restart the computer, or the network goes down, the “Clock out” button disappears and is in the “Clock In” format

Please help me! Thanks