FWIW: NSM won't delete archived reports
Was testing how NSM reports compare to the CSC-MA versions of the same reports this week. NSM console is running Version 2.1.1-R7-H4
I created both the CTA and the Flow reports to go to PDF. I then ran the schedule immediately and downloaded the Archived reports (zipped for some reason).
Afterward, I tried to delete those reports and it failed.
Ticket 43607012 is now open for this problem.