SwitchYard allows 'Transaction is not active' errors, not predictably reproduceable.

After discussion with EAP Tx SMEs, it seems possible this is related to SwitchYard's transaction interceptor code. EAP had similar symptoms with EJB transactions, an adjustment to the interceptor solved the issue.

Some resources:
https://issues.jboss.org/browse/WFLY-1346 // the Wildfly fix
https://bugzilla.redhat.com/show_bug.cgi?id=1008644 // EAP BZ
https://developer.jboss.org/thread/228598 // conversation on the topic
http://pastebin.test.redhat.com/341474 // Pastebin with sample code (may expire)

Possibly helpful code snippet:
} else if (txStatus == Status.STATUS_MARKED_ROLLBACK)

else if (txStatus == Status.STATUS_ROLLEDBACK) {
// handle reaper canceled (rolled back) tx case (see WFLY-1346)
// clear current tx state and throw RollbackException (EJBTransactionRolledbackException)
tm.rollback();
throw EjbLogger.ROOT_LOGGER.transactionAlreadyRolledBack(tx);