The first thing everyone does when they're going to upgrade NetBackup is to shutdown the daemons/services, right ? Oddly enough though the first thing an appliance wants to do when you upgrade it is to run a self-check (which creates a STU on the Master, creates a policy, runs a backup, & runs a restore), which requires that all daemons be running.
I propose that instead of running two self-checks (one before the upgrade and one after) that the appliance only run a single self-check after the upgrade completes.