Issue using static class properties within a Laravel job

I have some logic that works inside a controller but when I execute it in a job, QUEUE_DRIVER=database, I'm getting some unexpected behavior.

Within my job, I call a configure static method which sets a static property and then references it in the second (getFiles) method call.

    public function handle()
    {
        NICE::configure([
            'accessKey' => config('nice.credentials.accessKey'),
            'secretKey' => config('nice.credentials.secretKey')
        ]);

        $niceFiles = NICE::getFiles($this->contact->contactId);

    public static function getFiles($contactId)
    {
        $req = self::$guzzle->request('GET', self::apiURL('contacts/' . $contactId . '/files'), [
            'headers' => [

There error I'm getting is I'm apparently calling request() on NULL (self::$guzzle).

Symfony\Component\Debug\Exception\FatalThrowableError: Call to a member function request() on null

Is there some under-the-hood Laravel magic I'm missing when using static properties and classes in a queued job?

via Chebli Mohamed