I just found out that due to bug in Configurable Reports plugin, its Cron tasks will never run.

I am using the latest Configurable Reports plugin, version 3.8.0 (2019122000).

In block_configurable_reports.php method cron() of class block_configurable_reports, lines 182-185:

$lastcron = $DB->get_field('block', 'lastcron', array('name' => 'configurable_reports'));

if (!$lastcron and ($lastcron + $this->cron < time()) ) {

  return false;

}

The condition to exit from method by returning false should be if ($lastcron …, not (!$lastcron …) as it is now. Otherwise whenever the plugin never ever run its cron tasks before, it will always return, as $lastcron will be false.