On downstream (6.4.x) there is an error https://bugzilla.redhat.com/show_bug.cgi?id=1599625 about error during restart of master host with rollout plan. This problem doesn't happen on master, but both fix and test should to be created also for wildfly (to satisfy upstream and prevent similar problems to happen - by introducing a test).

Original problem:
Creating a rollout plan and restarting the dc host prevent the other hosts to connect to the master again. The slave hc is unable to connect giving the error JBAS014687: Resource is immutable, the dc shows many errors like:

JBAS012119: cancelled task by interrupting thread Thread[Host Controller Service Threads - 117,5,Host Controller Service Threads]