JBossTS is missing bridge part for TransactionTimeoutConfiguration.
org.jboss.jca.core.connectionmanager.tx.TxConnectionManagerImpl#getTimeLeftBeforeTransactionTimeout checks if transactionManager is instance of org.jboss.jca.core.spi.transaction.TransactionTimeoutConfiguration, but transactionManager comes from JBossTM, it is instance of com.arjuna.ats.jbossatx.jts.TransactionManagerDelegate in my case, that in turn implements org.jboss.tm.TransactionTimeoutConfiguration, thus check always fails.