I'm testing with 4.17.19.Final which is supposed to be in EAP 6.3.0.ER2. 

When I simulate fail of commit of the javax.resource.spi.LocalTransaction then the TM informs user in log with this message:
22:05:23,489 WARN  [com.arjuna.ats.jta] (EJB default - 7) ARJUNA016039: onePhaseCommit on < formatId=131077, gtrid_length=29, bqual_length=36, tx_uid=0:ffff7f000001:-52794c1e:53499c6c:43, node_name=1, branch_uid=0:ffff7f000001:-52794c1e:53499c6c:48, subordinatenodename=null, eis_name=java:jboss/xa-datasources/CrashRecoveryDS > (LocalXAResourceImpl@635955c6[connectionListener=4371ac17 connectionManager=7e0e6d1e warned=false currentXid=null productName=PostgreSQL productVersion=9.3.4 jndiName=java:jboss/xa-datasources/CrashRecoveryDS]) failed with exception XAException.XA_RBROLLBACK: org.jboss.jca.core.spi.transaction.local.LocalXAException: IJ001156: Could not commit local transaction

That's fine but the message says that onePhaseCommit was used which is not correct (in my case I have 2 resources - one XA and one CMR). 

It seems that this message comes from com.arjuna.ats.internal.jta.resources.XAResourceErrorHandler
Please, change the message to correspond with the number of resources being involved in the transaction - I mean when there are 2 resources there is not used one phase commit optimization.