Laravel horizon failure on high availability setup

I’m running two Laravel apps in a high availability setup, with a load balancer directing traffic between them.

Both apps use the same Redis DB (AWS ElasticCache) for queues , and are set up with Laravel Horizon.
Both apps have the same configurations and 3 workers each. "high", "medium" and "low".
Most jobs are running fine, but there’s one job that takes longer than others and is causing an issue.
The failing job is running on the ‘low’ worker.

So the job is processed by one horizon. It’s processing and after 1 minute and 30 seconds, the second laravel horizon is also taking the job and start processing it. Since this job can’t run in parallel, the job fails.

It looks like the lock system isn’t working properly, since both Laravel Horizon instances are taking the job.

Does horizon have a lock system or do I have to implement my own ?

I also have no idea why 90s after the job is taken by horizon, the 2nd horizon is taking it.

config/horizon.php

'environments' => [
    'production' => [
        'supervisor-1' => [
            'connection' => 'redis',
            'queue' => ['high', 'default', 'low'],
            'balance' => 'auto',
            'processes' => 1,
            'tries' => 1,
            'timeout' => 1250,
            'memory' => 2048,
        ],
    ],
],

config/queue.php

'connections' => [
    'redis' => [
        'driver' => 'redis',
        'connection' => 'default',
        'queue' => 'default',
        'retry_after' => 1260,
        'block_for' => null,
    ],
],