Laravel queue sometimes duplicates a job

I'm making a website crawler using Laravel 5.7. The queue is on Redis driver and I'm using laravel horizon to run the job. I want only one job to run or queued at the same time, however it sometimes duplicates a job and ends up running multiple instances of the same job simultaneously. Is there any way to guarantee that only one job is running at a time?

Job class

class MyJob implements ShouldQueue

{ use Dispatchable, InteractsWithQueue, Queueable, SerializesModels;

public $timeout = 30000;

public $tries = 1;

public function __construct($jobid = null)
{
    if (!$jobid) {
        $this->ra_jobid = substr(str_shuffle('1234567890abcdefghijklmnopqrstuvwxyz'), 0, 8);
    } else {
        $this->ra_jobid = $jobid;
    }
}

public function handle()
{
    Redis::funnel('RetrieveAucfanData')->limit(1)->then(function () {
        if (Redis::get('stop_job' . $this->ra_jobid)) {
            Redis::del('stop_job' . $this->ra_jobid);
            throw new JobManuallyStoppedException();
        }

        //crawl a website

    }, function () {
        return $this->release(60);
    });
}

public function failed(\Exception $exception)
{
    if ($exception->getMessage() == 'Job Manually Stopped') {
        Log::debug($exception->getMessage());
    } else {
        self::dispatch($this->ra_jobid)
            ->delay(now()->addSeconds(60));
    }

}

}

I want to queue this job again if the job failed unless it's manually stopped. I also want to put the job back to the queue if it hit the limit.

queue.php

<?php

return [

/*
|--------------------------------------------------------------------------
| Default Queue Driver
|--------------------------------------------------------------------------
|
| Laravel's queue API supports an assortment of back-ends via a single
| API, giving you convenient access to each back-end using the same
| syntax for each one. Here you may set the default queue driver.
|
| Supported: "sync", "database", "beanstalkd", "sqs", "redis", "null"
|
*/

'default' => env('QUEUE_DRIVER', 'redis'),

/*
|--------------------------------------------------------------------------
| Queue Connections
|--------------------------------------------------------------------------
|
| Here you may configure the connection information for each server that
| is used by your application. A default configuration has been added
| for each back-end shipped with Laravel. You are free to add more.
|
*/

'connections' => [

    'sync' => [
        'driver' => 'sync',
    ],

    'database' => [
        'driver' => 'database',
        'table' => 'jobs',
        'queue' => 'default',
        'retry_after' => 30,
    ],

    'beanstalkd' => [
        'driver' => 'beanstalkd',
        'host' => 'localhost',
        'queue' => 'default',
        'retry_after' => 30,
    ],

    'sqs' => [
        'driver' => 'sqs',
        'key' => 'your-public-key',
        'secret' => 'your-secret-key',
        'prefix' => 'https://sqs.us-east-1.amazonaws.com/your-account-id',
        'queue' => 'your-queue-name',
        'region' => 'us-east-1',
    ],

    'redis' => [
        'driver' => 'redis',
        'connection' => 'default',
        'queue' => 'default',
        'retry_after' => 300,
        'block_for' => 10,
    ],

],

/*
|--------------------------------------------------------------------------
| Failed Queue Jobs
|--------------------------------------------------------------------------
|
| These options configure the behavior of failed queue job logging so you
| can control which database and table are used to store the jobs that
| have failed. You may change them to any database / table you wish.
|
*/

'failed' => [
    'database' => env('DB_CONNECTION', 'mysql'),
    'table' => 'failed_jobs',
],

];