Before you build any agents to rebuild the cluster system file, please look in log and check to see if you have any errors messages like replication errors or index build errors. Another thing that can be causing your problem is the resouse.nsf, this file should not be replicate to another server. It should be available in one server. If you still have the busytime.nsf on your cluster server, that mean that the cluster manager has not build the cluster busytime db.
Run this command on the server console, to force adminp, to process any pending process that might have been stuck in qoueue, Tell Adminp Process All. The what the cluster db fo any error.
if you want to rebuild the db at off hour create a program doc, that run the Fixup and updall task onthe db. You can schedule this for any time.