Upgrade to Red Hat Satellite 6.10 fails with message 'ERROR: at least one Erratum record has migrated_pulp3_href NULL value'

Issue

• Red Hat Satellite upgrade to 6.10 from Satellite 6.9.8 or below, fails at content-switchover state with the following error message:

  Switch support for certain content from Pulp 2 to Pulp 3:
  Performing final content migration before switching content
  Checking for valid Katello configuraton.
  Starting task.
  2022-01-04 10:40:39 -0700: Importing migrated yum repositories: 141/224
  Content Migration completed successfully
  Performing a check to verify everything that is needed has been migrated
  
  Switching specified content over to pulp 3                            [FAIL]
  Failed executing foreman-rake katello:pulp3_content_switchover, exit status 1:
  ERROR: at least one Erratum record has migrated_pulp3_href NULL value
  Checking for valid Katello configuraton.
  \--------------------------------------------------------------------------------
  Scenario [Migration scripts to Satellite 6.10] failed.
  
  The following steps ended up in failing state:
  
   [content-switchover]
  
  Resolve the failed steps and rerun
  the command. In case the failures are false positives,
  use --whitelist="content-switchover
  

• Or, The content migration attempt in Red Hat Satellite 6.9.9 sometimes fails with the following error:

  Starting task.
  2022-05-26 11:38:05 +0200: Importing migrated yum repositories: 981/984
  ...
  Repositories with the following IDs and names have unmigrated errata:
  4748, Red Hat Enterprise Linux 7 Server - Extras RPMs x86_64
  ...
  Resync these repositories and then run 'reimport_all=true foreman-maintain content prepare'.