DRAFT INT-XXXX Tomcat fails with "Halting JVM startup: Administration console migration failed." error during an upgrade or migration

Symptoms

The following error is observed in the Tomcat log after an upgrade/migration:

FATAL com.appiancorp.common.web.StartupHaltingServletContextListener - Halting JVM startup: Administration console migration failed.
com.appiancorp.suiteapi.common.exceptions.AppianException: Administration console migration failed. (APNX-1-4282-000)
...
Caused by: java.lang.RuntimeException: Priority '1' is not unique

Cause

The migration of the primary database cannot be completed for one of the following reasons:

1. The migration has already occurred and is attempting to complete for a second time.
2. The database software/version cannot support the schema.

In order to determine the exact cause of the issue, the following information is necessary:

1. The exact version and hotfix the environment is being upgraded to and from.
2. The detailed steps followed to complete the upgrade/migration.
3. A SQL dump of the primary database.

Action

1. Gather the above information.
2. If it is determined that the database cannot support the schema, ...
3. If it is determined that the migration has previously been performed,