What is being suggested is that prior to upgrading other servers in the CUCM cluster, that you either monitor the Windows Cisco TFTP BuildDuraction perfmon counter or the RTMT DeviceBuildCount until they stop incrementing.
Once they have stopped then you can be assured that all the configuration files have been created. Do you have a separate TFTP server, or is enabled on the Publisher? Either way monitor either counter when it stops the proceed with upgrading the remaining servers in the cluster.
Hope this helps.
Regards
Allan.