GEO based records

I have the following geo based setup that gives back back a specific address back based on the client IP address.

For this I use powerdns with the geo plugin as the authoritive DNS and Unbound 1.13.1-1ubuntu5.14 as the DNS resolver.

In the test I use three clients located in the networks 192.168.21.0/24, 192.168.22.0/24 & 192.168.23.0/24.

In the test the client should get the right IP back based on the subnet.

The geo zone has the following setup:

When the client ask for z0.geo.example.com the client should get the answer:

client: 192.168.21.0/24 anwser: 192.168.20.2
client: 192.168.22.0 anwser: cname: client2.example.com.
client: 192.168.23.0/24 anwser: 192.168.20.1

When the clients 192.168.21.0/24 & 192.168.23.0/24 do the query at the same time both network do get the right address.

user@cl3:~$ host -vta z0.geo.example.com 192.168.20.183
Trying "z0.geo.example.com"
Using domain server:
Name: 192.168.20.183
Address: 192.168.20.183#53
Aliases: 

;; ->>HEADER<<- opcode: QUERY, status: NOERROR, id: 5105
;; flags: qr rd ra; QUERY: 1, ANSWER: 1, AUTHORITY: 0, ADDITIONAL: 0

;; QUESTION SECTION:
;z0.geo.example.com.            IN      A

;; ANSWER SECTION:
z0.geo.example.com.     10      IN      A       192.168.20.1

Received 53 bytes from 192.168.20.183#53 in 18 ms

At the moment a client from 192.168.22.0/24 does the question all the answers returns the CNAME back.

I would expect that only the clients from 22 get the CNAME returned.

This is a known bug in this version?