I suppose the easiest way to reproduce, would be to create a single node cluster with K3s and make it a master. Apply the generated ccm-linode.yaml following the howto and then try to LoadBalance a service. It will fail. Add an agent node to the cluster and then it will succeed.
If I'm correct about this, it is limiting our options.
For example, I have setup a HA K3s for rancher and planning to use it, to create more clusters. The 3 control plane nodes should be able to do the whole job. There should be no need to add agent nodes, because you would also need at least 2.
I thought I'd just reach out and see if this is something I'm doing wrong and there is a label, or an annotation I'm missing, that might solve my problem.