I have 3 DC's each running AD integrated DNS. They are all configured with the same Conditional Forwarders (for our 3 discontiguous Domains) and they all have the same External Forwarders (OpenDNS) in the same order. When I ping servers in one of those Domains defined under Conditional Forwarding from the 2 'Happy DC's' there is no problem. The Domain is properly appended and the IP is correctly resolved and Relies come through. When I do the same ping from the 3rd DC, the Domain name is correctly appended but the IP that is returned is actually the IP of a random External DNS Server from the OpenDNS (not the ones that are configured as the External Forwarders).
Does anyone have an idea as to why my stray DC is behaving oddly? This is a relatively new behavior. Previously they were all acting normally. Other than Windows Patches, I am not aware of any changes to the DC. All of them are at same Patch status.