One template on Template Node preserves the existing behavior. Agents may run on another selected node, but Proxmox requires both the source template disks and the clone's target storage to be shared for that cross-node clone.
Matching template on each Agent Node supports clusters with local storage. Each selected node must have its own template, with a distinct cluster-wide VM ID, matching the configured tag or name regular expression. Jenkins resolves the newest local match before placement.