WildFly typically specifies integration properties at the EMF (SF) level and then uses the EMF for creating:

1. container managed persistence contexts (either SynchronizationType.UNSYNCHRONIZED or SynchronizationType.SYNCHRONIZED)
2. extended persistence contexts
3. app managed persistence contexts

To use this new optimization, I think that applications should opt in, by specifying the required settings, but by default, we should not expect WF to set the flush mode.