Hibernate CollectionOfElements EAGER fetch duplicates elements

I stepped into the same problem – when you set the FetchType.EAGER for a @CollectionOfElements, the Hibernate tries to get everything in one shot, i.e. using one single query for each entry of element linked to a “master” object. This problem can be successfully solved at a cost of N+1 query, if you add the @Fetch (FetchMode.SELECT) annotation to your collection.
In my case I wanted to have a MediaObject entity with a collection of its metadata items (video codec, audio codec, sizes, etc.). The mapping for a metadataItems collection looks as follows:

@CollectionOfElements (targetElement = String.class, fetch = FetchType.EAGER)
@JoinTable(name = "mo_metadata_item", joinColumns = @JoinColumn(name = "media_object_id"))
@MapKey(columns = @Column(name = "name"))
@Column (name = "value")
@Fetch (FetchMode.SELECT)
private Map<String, String> metadataItems = new HashMap<String, String>();