Fix?

ansible/inventories/production/host_vars/rpi0.home.jthan.io/vars.yaml

@@ -1,5 +1,5 @@
 private_domains:
-  home.jthan.io:
+  - home.jthan.io:
     records:
       - type: A
         name: "router.home.jthan.io"

ansible/roles/unbound/tasks/templates/unbound.conf.j2

@@ -615,7 +615,7 @@ server:
 	# Allow the domain (and its subdomains) to contain private addresses.
 	# local-data statements are allowed to contain private addresses too.
 	{% for domain in private_domains %}
-	private-domain: "{{ domain }}"
+	private-domain: "{{ domain['name'] }}"
 	{% for record in  domain['records'] %}
 	local-data: "{{ record['name'] }} {{ record['type'] }} {{ record['value'] }}"
 	{% endfor %}