a job was executed twice at the same time

[xiaopangniuniu]

The version of my redis is 4.1.2, rq is 1.10.1
I use supervisor to create 5 workers at most like below:
command=rq worker --with-scheduler -P /myworker_path -c settings high default low
numprocs=5

All of my jobs go to default queue currently. Most of the time, job is executed once as expected.
But sometimes, I found some jobs were executed twice at the same second.

I‘m new to use RQ and still learning. Is it the right way I use the rq worker? What I want to do is to use 5 workers to process the same queue to improve the scalability of my tool.

Thanks a lot.