I have the same problem with Unbound on my OpenWrt router. Did you find a solution?
Edit: Never mind. Turns out I had dnsmasq (which is forwarding DNS requests to unbound) set to "Filter SRV/SOA service discovery" for some reason. Unset that and it's working now.
Edit: Never mind. Turns out I had dnsmasq (which is forwarding DNS requests to unbound) set to "Filter SRV/SOA service discovery" for some reason. Unset that and it's working now.