Preconditions:

Create a parent entity with OneToMany association to its children:

Parent {
@OneToMany(cascade = CascadeType.ALL, orphanRemoval = true, mappedBy = "parent", fetch = FetchType.EAGER)
@Size(min = 0, max = 4)
List<Child> children = new ArrayList<Child>();

// invoke inside transaction
public void addChild(Child child)

}

Reproduction steps:
Create a parent entity and try to add five children, one at a time.

Result:
All five children successfully created w/o throwing validation errors

Expected result:
Validation error when adding the 5th child.

Additional notes:
org/hibernate/event/internal/DefaultFlushEntityEventListener.java:isUpdateNecessary() method returns false for described above steps, but should return true since collection size is changing and this must be validated.