If I delete a repeat of a repeated event, I get the following error:
 Argument 2 passed to Joomla\CMS\Application\BaseApplication::triggerEvent() must be of the type array or null, int given, called in .../administrator/components/com_jevents/controllers/icalrepeat.php on line 848

There is the following line:
$res = JFactory::getApplication()->triggerEvent('onDeleteEventRepeat', $id);
$id is an integer. The api expects an array (https://api.joomla.org/cms-3/classes/Joomla.CMS.Application.BaseApplication.html).

Installed versions:
Joomla: 3.9.16
Jevents: 3.4.54 Stable