Bill,
By 'current nodes' I mean ones we are backing up daily, not ones
retired but somehow still in the database.

I had misread or misremembered the description of what happens when a
management class is deleted, and expected any files, inactive or
active, bound to a deleted to be rebound to the default management
class for the domain, etc.  In a hurry, I couldn't find the
documentation on that to clarify the behavior.

I did run the query you suggested; select ll_name, state,
backup_date, deactivate_date, class_name from backups where node_name
= '<node-name>'   The result was 'ANR2034E SELECT: No match found
using this criteria'.

This makes me wonder whether the original query had a, subtle to me
but glaring to others, logic error.  I am now running a simpler
query; "select node_name from backups where class_name =
'<mystery_class>'".  It may run for awhile, so I am sending this
ahead in hope of additional suggestions.

With my thanks,
Keith Arbogast