Solution:
The only explanation I could think of is that your job takes longer then expected, therefore it times out, and it gets retried again. You might wanna checkout the timeout configuration for jobs in laravels docs
https://laravel.com/docs/8.x/queues#timeout
Also you can specify how many times the job might be attempted before failing, by default its 3 I guess
https://laravel.com/docs/8.x/queues#max-job-attempts-and-timeout