Hello
On the "Availability report" page, the following error in the calculations was noticed in the web monitoring. Now I'll try to describe:

Go to In Reports → Availability. Then set the parameters as in the screenshot #1. As a result, the calculations were performed and the result was obtained as in the screenshot #2.

If you select this interval on the "Latest Data" page, you can see that the problem was two minutes(screenshot #3). The length of the interval is 10 minutes. Of this, the problem was 100 * 2/10 = 20%, and in the "Accessibility report" the state of the problem is 36%.

We make debug function calculateAvailability into a file include/triggers.inc.php.

It was determined that in the "availability report" the calculation of the share of the problem starts from the moment of the first occurrence of the event in the selected interval.
And if you change the parameters, move the lower bound, the proportion of the problem in the interval will not change. This can be seen in the screenshots #4 and 5.

Tell me, please, this functioning of the calculations is correct? If yes, explain the meaning of these calculations.

Thank you