MDB is looking up UserTransaction even if it isn't Bean Managed

Investigating on a use case I've seen that MDB comes to org.jboss.jca.adapters.jdbc.WrapperDataSource looking up for UT. It fails with this exception

javax.naming.NamingException: JBAS014237: Only session and message-driven beans with bean-managed transaction demarcation are allowed to access UserTransaction [Root exception is java.lang.IllegalStateException: JBAS014237: Only session and message-driven beans with bean-managed transaction demarcation are allowed to access UserTransaction]

the problem is exposed running
org.jboss.as.test.integration.ejb.mdb.MDBTestCase