Where commit on an XAResourceRecord fails in such as way as to return TwoPhaseOutcome.FINISH_ERROR, no error is seen at the JTA (actually JCA XATerminator) layer, effectively making the commit failure invisible except by reading the WARN in the log files. Core does not consider this situation a heuristic, as with a single record there is no inconsistency as such. However, to a user it is an error - they asked for a commit but got a rollback.