Some Zombie VMs are a remnant of some bug with Fly apps using the experimental release_command, but one which Fly allegedly has since fixed. You’d have to nerd snipe Fly engs to get the zombie culled: lingering connections and ghost vms. - #2 by ignoramous
Or, if you’re on a paid plan (ex $29/mo), then you can email support: I can’t deploy the application!!! - #3 by undefined (see img).