The laravel horizon pending job can not execued

Verytime product 20 jobs but the just exec 3 jobs.Ahe other jobs were pending. And the job was fast,not spend too much time.

//the config 
    'warning' => [
                'processes' => 40,
                'maxProcesses' => 30,
                'minProcesses' => 10,
                'connection' => 'redis',
                'queue' => [
                    'warning-post',
                    'warning-topic',
                ],
                'memory' => 256,
                'timeout' => 300,
                'tries' => 1,
                'balance' => 'auto',
            ],