FireCloud creates non-preemptible VMs for a preemtible workflow, racking up huge charge

Hi FireCloud Team,

I noticed a $308 charge for ~6000 hours of compute time on a "standard" (non-preemptible) VCPU, while the workflow I'm running is preemptible and designed to shut off after 24 hours. Also, the VMs are showing up in my Google Cloud Compute Engine page, which my colleagues say is not supposed to happen.

Would you know what is causing this? Is it possible to have the charge refunded?

Thanks,
Jeff