The idea was that you would reserve a job in a tube, do some work, then move that job to another tube upon success atomically, without the need to delete the job, then create the job in the new target tube. The problem is that if you create the job in the new tube before deleting, the TTL could kick in and return the job to the original tube, meaning you have the same job in both tubes. The other alternative is to delete the job then put it in the target tube. However, if your worker process dies during this step, you may end up losing the job.