Do cleanup and generate of schedules under cron group lock

Author: paveq

app/code/Magento/Cron/Observer/ProcessCronQueueObserver.php

@@ -199,8 +199,6 @@ public function execute(\Magento\Framework\Event\Observer $observer)
         $phpPath = $this->phpExecutableFinder->find() ?: 'php';
 
         foreach ($jobGroupsRoot as $groupId => $jobsRoot) {
-            $this->_cleanup($groupId);
-            $this->_generate($groupId);
             if ($this->_request->getParam('group') !== null
                 && $this->_request->getParam('group') !== '\'' . ($groupId) . '\''
                 && $this->_request->getParam('group') !== $groupId
@@ -234,6 +232,9 @@ public function execute(\Magento\Framework\Event\Observer $observer)
                 continue;
             }
 
+            $this->_cleanup($groupId);
+            $this->_generate($groupId);
+
             /** @var \Magento\Cron\Model\Schedule $schedule */
             foreach ($pendingJobs as $schedule) {
                 $jobConfig = isset($jobsRoot[$schedule->getJobCode()]) ? $jobsRoot[$schedule->getJobCode()] : null;