Why does content migration to Pulp 3 fails due to corrupted or missing content but file /tmp/unmigratable_content-*/Rpm is empty in Red Hat Satellite 6.9?

Issue

• Content migration fails on corrupted or missing RPM packages:

  root@satellite# satellite-maintain content migration-stats
  [...]
  ============Missing/Corrupted Content Summary================
  WARNING: MISSING OR CORRUPTED CONTENT DETECTED
  Corrupted or Missing Rpm: 1/140788
  Corrupted or missing content has been detected, you can examine the list of content in /tmp/unmigratable_content-20220613-12921-kvpcs2 and take action by either:
  1. Performing a 'Validate Content Sync' under Advanced Sync Options, let it complete, and re-running the migration
  2. Deleting/disabling the affected repositories and running orphan cleanup (foreman-rake katello:delete_orphaned_content) and re-running the migration
  3. Manually correcting files on the filesystem in /var/lib/pulp/content/ and re-running the migration
  4. Mark currently corrupted or missing content as skipped (foreman-rake katello:approve_corrupted_migration_content).  
  This will skip migration of missing or corrupted content.  Any skipped content will be re-synced if it is still available from the upstream repository.
  

• Resulting file /tmp/unmigratable_content-*/Rpm does not list any RPM package:

  root@satellite# cat /tmp/unmigratable_content-20220613-12921-kvpcs2/Rpm
  filename,id,Repository Name,Content View Name,Content View Version
  root@satellite#
  

• How can I find information about the missing or corrupted package(s)?