dns: response only udp not detected as dns
If only a DNS response is seen on a UDP session it will not be detected and parsed as DNS with the default configuration.
Enabling stream.midstream does allow it to be picked up, but this is just an unintended side affect as stream.midstream is really a TCP setting. Likewise, enabling async streams allows this scenario to work for TCP DNS, but doesn't affect UDP DNS.
My feeling is that this should just work with the default configuration.