i've setup a forwarding zone on a RHEL6 Bind server like this:

zone "office.local" IN {
        type forward;
        forward only;
        forwarders { 192.168.0.2; 192.168.0.3; };
};

when i try to query using dig @127.0.0.1 monitorsms.office.local i see the following message in the syslog:

client 127.0.0.1#39376: query: monitorsms.office.local IN A + (127.0.0.1)
validating @0x7ff7640357d0: monitorsms.office.local A: bad cache hit (monitorsms.office.local/DS)

google tells me, that there is an issue with DNSSEC, but both servers do not have DNSSEC configured and thus do not send any DNSSEC records.

What's wrong with my configuration?