Status: Verified (View Workflow)
Affects Version/s: None
Fix Version/s: 7.1.0.CR1
Hibernate ORM 5.1 introduced a new feature to enable multi-loading entities, HHH-7572. 
This feature has some bugs that are fixed upstream in 5.2.2 that have not been backported to 5.1:
- HHH-10617 : Returns results in the same order as specified IDs 
- HHH-10984 : Have multiLoad not return (unflushed) DELETED entities 
Without these bugfixes, results that are returned are surprising for the following reasons:
- the returned list of results does not correspond to the list of specified IDs;
- the resulting list can have a different length from the list of specified IDs;
- the resulting list excludes results for entities that don't exist (instead of a null value that corresponds to the specified ID);
- the resulting list can contain duplicated entities that are not due to duplicated IDs being specified; instead, duplicates are due to left outer joins;
- the resulting list can contain (non-flushed) deleted entities.
The main reason I think this could be a blocker is that returning a deleted entity could corrupt data, depending on what the application ultimately does with the deleted entity.
The fix for HHH-10617/HHH-10984 changes the default by making the resulting List as expected: the i-th entity returned corresponds with the i-th specified ID, or null when that entity does not exist or has been deleted (regardless of whether this operation was flushed).