Following warning can be found in log:

15:48:45,085 WARN [org.jboss.as.jaxrs] (MSC service thread 1-3) WFLYRS0018: Explicit usage of Jackson annotation in a JAX-RS deployment; the system will disable JSON-B processing for the current deployment. Consider setting the 'resteasy.preferJacksonOverJsonB' property to 'false' to restore JSON-B.

Following parameter needs to be used when the EAP is being started:

-Dresteasy.preferJacksonOverJsonB=true