In some cases the migration of historical data may fail or get stuck. If users are on old and out of support version such 11.3 or R12.0 SP1/SP2, then in rare cases data may not fully migrate.
The data migration takes place after the artifacts. Large amount of data or row counts can sometimes result in DB timeouts.
Release : 12.2, 12.3
Component : Workload Automation DE
Note: If data moves result in primary key or sql constraints issue, then older database may have been modified. See this link fix the db constraints issue.