JPAContainer problem with Or-Filter

Hi Folks,
when using JPAContainer with the Or-Filter, i get the same Items multiple times in the filtered container.
Here's my sample code:

Test Entities:

@Entity
public class TestEntity {
    @Id
    @GeneratedValue(strategy=GenerationType.IDENTITY)
    private Integer id;
    
    @ManyToMany
    private Collection<TestEntity2> testEntities2 = new HashSet<TestEntity2>();

    private String someField;

    getters/setters...
}

@Entity
public class TestEntity2 {
    @Id
    @GeneratedValue(strategy=GenerationType.IDENTITY)
    private Integer id;
    
    private String someField;

    getters/setters...
}

Test Code:

// Create containers for the 2 entity-types
JPAContainer<TestEntity> container = JPAContainerFactory.make(TestEntity.class, ...pu...);
JPAContainer<TestEntity2> container2 = JPAContainerFactory.make(TestEntity2.class, ...pu...);

// Create entities
TestEntity testEntity = new TestEntity();
// Add and retrieve to have Object with id set
TestEntity2 testEntity2ToAdd1 = container2.getItem(
        container2.addEntity(new TestEntity2())).getEntity();
TestEntity2 testEntity2ToAdd2 = container2.getItem(
        container2.addEntity(new TestEntity2())).getEntity();

// Add to collection
testEntity.getTestEntities2().add(testEntity2ToAdd1);
testEntity.getTestEntities2().add(testEntity2ToAdd2);

// Add to the container
container.addEntity(testEntity);

// Create an Or-filter for the just created TestEntity2-entities
Or or = new Or(
        new Compare.Equal("testEntities2.id", testEntity2ToAdd1.getId()),
        new Compare.Equal("testEntities2.id", testEntity2ToAdd2.getId()));

// Add the filter
container.addContainerFilter(or);

// Will output the ID of testEntity 3x
System.out.println(container.getItemIds());

This is the SQL-Statement created:
SELECT t0.ID FROM TESTENTITY_TESTENTITY2 t4, TESTENTITY_TESTENTITY2 t3, TESTENTITY2 t2, TESTENTITY2 t1, TESTENTITY t0 WHERE (((t1.ID = ?) OR (t2.ID = ?)) AND (((t3.TestEntity_ID = t0.ID) AND (t1.ID = t3.testEntities2_ID)) AND ((t4.TestEntity_ID = t0.ID) AND (t2.ID = t4.testEntities2_ID)))) ORDER BY t0.ID ASC

I am no SQL-Expert, but this select statement looks pretty odd to me.

If i add a third entity to the collection and append it to the Or-filter, testEntity is 19x in the container.
I tried Collection, Set and List as type of "testEntities2".

Am i doing somethig wrong or is this a Bug?

The And-filter seems to work, allthough the SQL-Statement looks odd too...

Environment info:
<!ENTITY vaadin.version "7.3.10">
<dependency org="com.vaadin.addon" name="jpacontainer" rev="3.2.0" />
<dependency org="org.eclipse.persistence" name="eclipselink" rev="2.6.0" conf="default"/>
<dependency org="mysql" name="mysql-connector-java" rev="5.1.35" />

Should be the newest version of all used libs

Thank you,
Felix

I worked around the problem by setting an QueryModifierDelegate an always make the queries distinct.
But i would be really interested if i found a bug or just having some faulty reasoning here.