Can you enable TRACE logging for org.jboss.as.jpa + org.hibernate. That might be a little overkill but it would be nice to see what is shown prior to the warning about the deprecated persistence provider (should help us understand why a new EMF is obtained).

https://docs.jboss.org/author/display/WFLY8/JPA+Reference+Guide#JPAReferenceGuide-Troubleshooting explains how to enable TRACE logging in WildFly.