Envers always collects changes for audited objects in global (global per sessionFactory instance) application map (auditConfiguration.auditSyncManager.auditSyncs<Transaction, AuditSync>) even if transaction is inactive.
It leads to memory leak in application if there were changes (insert/update/delete) for versioned objects outside of transaction (transaction.isActive() == false) because in this case transaction is not committed where collected changes for current transaction are removed from global map.
Possible solution is patch Envers to check if transaction is active (AuditEventListener in onPostInsert/onPostUpdate/onPostDeleteonCollectionAction methods) before starting collect changes for audited object.
Skip collecting (to prevent memory leak) if transaction is inactive and log WARN message to indicate problem ("Couldn't create revision for entity $
because transaction is not active.")