Previous versions of JBoss EAP 6, when a distributed web session was being accessed while another node was abruptly leaving the cluster, a lock acquisition could, in some instances, fail. When this occurred it resulted in the following exception:
RuntimeException: JBAS018060: Exception acquiring ownership of <session-id>
The root cause of this issue was that the lock acquisition did not take into account that a cluster node might leave the cluster at exactly the same time, resulting in the lock acquisition failure.
This issue has been addressed and the exception no longer presents.