Cinder volume fails to transition to reserved state after instance shelving due to stale attachment

Issue

• After shelving an instance, the associated Cinder volume does not move into the reserved state.
• The cinder volume_attachment table contains two overlapping records for the same volume:
  • One with status attached (stale/old)
  • One with status reserved
• The affected volume is a boot volume, therefore:
  • The volume attachment cannot be deleted directly with the Cinder CLI.
  • The volume cannot be detached from the instance through the Nova API.