Steve Ebersole commented on an issue
Hibernate ORM / Bug HHH-3949
Intrumentated to one relations can not be join fetched
1) Relation Person -> Vehicle is annotated
    @OneToOne(optional=true, mappedBy="driver", fetch=FetchType.LAZY)
    @LazyToOne(LazyToOneOption.NO_PROXY)
    private Vehicle vehicle;

2) Both entities are instrumented with Javassist

3) Query (HQL or Criteria) Person and Vehicle: from Person p left join fetch p.vehicle
=> SQL query is correct but Vehicles...