When changes are made to the NAMED files on the primary DNS server the files are not transferred to the secondary DNS servers.
The zone transfers must not be taking place. Make sure that when the NAMED files on the primary are edited that the serial number in the SOA record is being incremented. Also after making changes on the primary DNS server you have to restart DNS (@TCPWARE:RESTART DNS) in order for the changes to become “live”. The secondary servers will compare the serial numbers every “refresh” period and start a zone transfer to get the updated file.