I set up the preemptible as 1, but the job was re-run 4 times

Dear Firecloud team,

There should something wrong with the preemptible. I set the value as 1, but it rerun 4 times.
Here is my workflow id:
Workflow ID:2370d038-a69e-4951-b299-a89478084f89

Thanks,
Hailei