After upgrading to Clarity 13.3:
In Oracle, the upgrade fails with a unique constraint message.
In MSSQL, upgrade is successful but ideas will not be visible after upgrade.
This is caused by corrupted records in the PRJ_OBS_ASSOCIATIONS table created prior to the upgrade.
Reference TEC612565 for further information on the data corruption in the PRJ_OBS_ASSOCIATIONS table
This issue is tracked for resolution as CLRT-74224 and its fixed in CA PPM 14.3