[Pdns-users] pdns-recursor returning bad data intermittently

[abang at t-ipnet.net]

 > mydomain.net=172.17.18.241;172.17.18.242

maybe you have different zone data on your auth servers. What is the 
result of

# dig @172.17.18.241 smtp.mydomain.net.

and

# dig @172.17.18.242 smtp.mydomain.net.